SAN DIEGO -- A man who lied to police about his friend's whereabouts when a woman and her son were strangled and also helped fake a DNA test to hide the infant's paternity, was convicted Friday of conspiracy to obstruct justice.

Maxwell Corn, 25, faces up to three years in state prison when he is sentenced Dec. 11 by Judge Bernard Revak, who heard the case without a jury.

Corn was best friends with Dennis Potts, who last month was convicted of the July 26, 2006, murders of Tori Vienneau and her 10-month-old son, Dean Springstube.

Corn told police that Potts -- who faces life in prison without parole when he's sentenced next week -- was with him continuously from 5 p.m. to 8 p.m. the day of the murders, the judge said. Cell phone records and a security camera at a fast-food restaurant showed that was not the case, he said.

Being wrong about Potts' whereabouts would be understandable, but Corn also lied about a DNA test Vienneau sought to learn the identity of her son's father, in which he substituted a sample of his DNA for Potts.

It's believed that the woman's request for a re-test under court supervision provided the motive for the murder, and Potts was eventually proved to be the father.

"If Mr. Corn had just told police the truth about the DNA, he wouldn't be here," Revak said.

There was no argument that some of the overt acts called for under the conspiracy law took place, and there was enough circumstantial evidence that Corn and Potts had at least a tacit agreement to hide information from police, the judge said.

"What impresses me most about these two young men is not only the nature of their relationship, but their stories are in lockstep," Revak said. "That is very unusual."

Deputy District Attorney Per Hellstrom told jurors in Potts' trial that the defendant deleted his text messages and altered his cell phone records. He had dinner plans with Vienneau the night she was killed, he said.

Hellstrom told the jury Potts surprised Vienneau in her apartment, knocked her unconscious, strangled her with the cord of a hair-straightening iron and ripped her blouse to make it appear to be a sexual assault.

Potts then hung the baby in his crib with a cell phone charger cord, the prosecutor said.

Vienneau's mother said after Corn's conviction that the "senseless" loss of her daughter "stripped me of all my identity."

Dayna Herroz said she "honors her daughter and grandson" by counseling family members who've lost loved ones to homicide or other sudden causes.

Corn was allowed to remain free on bond pending sentencing.