A forensic expert testified Tuesday that scientific evidence doesn't link a former Mount Kisco police officer to an immigrant's beating death.

The Westchester County expert told a White Plains jury that none of the clothing or fingernail samples taken from Rene Perez's body belonged to George Bubaris. The expert also said there's no evidence that the Guatemalan immigrant was ever inside Bubaris' police cruiser on April 28, 2007.

The testimony came on the same day jurors watched 60 minutes of surveillance video of Perez at a Laundromat hours before his death. Perez appeared to be drunk and was holding his stomach before making a 911 call for help at a pay phone.

The prosecution claims Bubaris beat Perez then dumped him in another jurisdiction, where he later died from internal bleeding. However, the defense maintains that Perez, a known drunk, died from self-inflicted injuries that may have been caused by a fall.

A medical examiner and three Bedford police officers are scheduled to testify next in Bubaris' manslaughter trial.