State of Minnesota, Respondent, vs. Puissance Jhovar Andersen, Appellant.

may not be cited except as provided by

Minn. Stat. § 480 A. 08, subd. 3 (1996).

 STATE OF MINNESOTA

 IN COURT OF APPEALS

 C7-97-1624

State of Minnesota,

Respondent,

vs.

Puissance Jhovar Andersen,

Appellant.

 Filed June 30, 1998

 Affirmed

 Davies, Judge

Hennepin County District Court

File No. 96089253

Hubert H. Humphrey III, Attorney General, 1400 NCL Tower, 445 Minnesota St., St. Paul, MN 55101 (for respondent)

Michael O. Freeman, Hennepin County Attorney, Beverly J. Benson, Assistant County Attorney, C-2000 Government Center, Minneapolis, MN 55487 (for respondent)

Lawrence W. Pry, Assistant State Public Defender, 875 Summit Ave., Room 371, St. Paul, MN 55105 (for appellant)

Considered and decided by Davies, Presiding Judge, Crippen, Judge, and Harten, Judge.

 U N P U B L I S H E D O P I N I O N

 DAVIES, Judge

Appellant challenges his convictions for aiding and abetting both burglary and aggravated robbery. We affirm.

 FACTS

During the early morning hours of October 8, 1996, appellant Puiassance Jhovar Andersen and three male companions broke into the Minneapolis apartment of three young women. They threatened the women with knives, and one of the other three men twice raped two of the women. They took money, jewelry, and other items of personal property and left in a car belonging to one of the women.

Appellant was arrested that night in Eau Claire, Wisconsin. He was later charged with aiding and abetting first-degree criminal sexual conduct, aiding and abetting first-degree aggravated robbery, and aiding and abetting first-degree burglary.

A jury acquitted appellant of aiding and abetting criminal sexual conduct but found him guilty of the remaining charges. The court sentenced appellant to an aggregated term of 154 months (12 years, 10 months) in prison. This appeal followed.

 D E C I S I O N

"Rulings on evidentiary matters rest within the sound discretion of the trial court." Caldwell v. State, 347 N.W.2d 824, 826 (Minn. App. 1984). Such rulings will not be reversed absent a clear abuse of that discretion. State v. Jones, 500 N.W.2d 492, 494 (Minn. App. 1993), review denied (Minn. June 9, 1993).

 I. Admission of Letter

While in the Eau Claire County Jail, appellant wrote to a friend. In the letter, appellant discussed what one of his companions should say about their involvement in the crimes. A jail regulation regarding outgoing mail required that the letter be unsealed. A jailer read and seized it. Before trial, appellant moved to have the letter excluded. The trial court denied the motion, and the letter was admitted as evidence. On appeal, appellant argues that the jailer's search of the letter violated state and federal constitutional proscriptions against unreasonable searches and seizures.

A search of the outgoing mail of a pretrial detainee based on a jail regulation which is constitutionally valid is not an unreasonable search. * * *

Furthermore, an unlawful search or seizure within the meaning of the Fourth Amendment occurs only when an individual's expectation of privacy is invaded.

 State v. Cuypers, 481 N.W.2d 553, 556 (Minn. 1992).

The Eau Claire County Jail has written regulations regarding inmate mail, including:

General [outgoing mail] is to be unsealed and privileged mail is to be sealed. All mail is subject to a general inspection for contraband, threat to security of the jail and/or persons.

According to appellant's testimony at the Rasmussen hearing, jail personnel did not inform him about the outgoing mail regulations. Appellant admitted, however, that he had been told by other inmates that any outgoing letter should remain unsealed "[f]or contraband reasons." Appellant did not interpret this as meaning the unsealed letter would be read.

Appellant cites Cuypers for the proposition that he retained a reasonable expectation of privacy in his unsealed letter because jail personnel had not informed him about the jail's outgoing mail regulation. But in Cuypers, it was the defendant's "knowledge" of the mail regulation that "destroy[ed] any expectation of privacy [the defendant] may otherwise have had in his outgoing mail." Cuypers, 481 N.W.2d at 557. The same is true here. Because appellant had knowledge that outgoing mail was to be unsealed and could be searched for contraband, he had no expectation of privacy in the letter that was seized by jail personnel.

The trial court did not err in admitting appellant's letter.

 II. Hearsay Statements

Rachel Kemptner testified at trial that appellant and his three companions showed up at her St. Paul apartment within hours of the crime. Kemptner testified to self-inculpatory statements made by Antonio Burton, one of the three companions. Appellant argues that the trial court violated his right to confront his accusers when it admitted these hearsay statements.

The trial court admitted Kemptner's account of Burton's comments on the basis that they were statements against penal interest. But the statements seem to have been braggadocio, which lacks the indicia of truthfulness usually associated with statements against penal interest.

The statements could be properly admitted, however, as adoptive admissions. Minn. R. Evid. 801(d)(2)(B) provides that a statement is not hearsay if it is offered against a party and is "a statement of which the party has manifested an adoption or belief in its truth." To meet the requirements of the confrontation clause, the adoptive admission must

be manifested by conduct or statements which are unequivocal, positive, and definite in nature, clearly showing that in fact defendant intended to adopt the hearsay statements as his own.

 Village of New Hope v. Duplessie, 304 Minn. 417, 425, 231 N.W.2d 548, 553 (1975) (emphasis in original).

Here, appellant was present when Burton made the statements to Kemptner about taking the victims' electronic equipment, about having the keys to the car of one victim, and about having sex with the victims. In response to Burton's comments about the rapes, appellant said to Burton: "Why did you do that, you're sick." Appellant also joined in the statements by giving details about one of the victims and about how he had taken one victim out of bed and put her on the floor. Appellant's direct responses to Burton's statements, along with his participation in the descriptive details of the crimes, is sufficient to indicate his adoption of Burton's statements.

At one point, appellant responded to Burton's statements with: "You are stupid. Shut up. Stop running your mouth." This was not a disclaimer of the truth of Burton's statements. The trial court did not err in allowing Kemptner to testify about Burton's statements.

 III. Cross-Examination of Witness

"The manner and scope of cross-examination, which generally should be wide-ranging, rests within the discretion of the trial court." State v. Langley, 354 N.W.2d 389, 401 (Minn. 1984). An appellate court will not reverse the trial court's decision absent an abuse of that discretion. Id.

As part of a plea agreement, Victor Porter, one of appellant's companions on the night of the crimes, agreed to testify at appellant's trial. In exchange for Porter's testimony, the Hennepin County prosecutor agreed to dismiss all charges against him except one first-degree burglary charge. Appellant was allowed to cross-examine Porter concerning this agreement. But appellant also sought to question Porter about an unrelated felony charge pending against him in Ramsey County, seeking to show that the pending charge may have affected Porter's testimony. Appellant argues that the trial court's denial of this request was a violation of his constitutional right to confront and cross-examine witnesses.

Whether Porter may have thought he could improve his situation in Ramsey County by testifying against appellant in Hennepin County is speculative. Appellant offered no evidence of any agreement either between Porter and Ramsey County prosecutors or between Ramsey and Hennepin County authorities. Further, jurors were already aware of the Hennepin County plea agreement and its direct effect on Porter's situation. Thus, the jurors knew Porter had reason to favor the prosecution in his testimony. The trial court did not err in prohibiting appellant from cross-examining Porter about the charge pending in Ramsey County.

  Affirmed.