FARMINGTON — The man, who murder suspect Juan Contreras said gave him marijuana laced with bath salts the night before 81-year-old Grace Burton was stabbed to death, testified Wednesday he doesn’t remember if he smoked with him but if he did there were no bath salts.

Bath salts are “not part of my world,” James Ben Sweenheart of Wilton said on the witness stand in Franklin County Superior Court on the third day of Contreras’ murder trial.

Contreras, 28, is charged with stabbing Burton 35 times in her home at Margaret Chase Smith Apartments at 195 Fairbanks Road in Farmington on June 21, 2011.

His attorneys said in opening statements that it’s a case of involuntary intoxication, because Contreras smoked marijuana he didn’t know contained bath salts before he killed Burton.

Sweenheart, who was granted immunity from prosecution in exchange for his testimony, said he remembered sitting near Contreras at Front Street Tavern in Farmington the night of June 20, 2011. He said he doesn’t remember whether he smoked marijuana with him that night, but it would not have had bath salts.

Sweenheart said he grows his own marijuana — six plants — in his home and has shared a rolled joint with people outside the bar. He said he doesn’t remember smoking with Juan and only takes joints outside his home.

According to court documents, Contreras said a man with long hair who looked like Jesus invited him to smoke a pipe with marijuana outside the bar. After smoking it, the man told Contreras it was laced with bath salts, the documents said.

Sweenheart testified he has never used, never tried, never laced a joint and shared it with anyone. He also said he had no ill effects from what he took that night.

“I’ve never had anything to do with (bath salts), ever,” he answered Assistant Attorney General Lisa Marchese. “Bath salts are something my mother puts in the tub to smell nice.”

Sweenheart also testified he did not go on to The Dugout Bar & Grill on Broadway in Farmington with Contreras that night. He said that night is the only time he has ever seen him.

Front Street Tavern bartender Steven Martin testified Sweenheart and Contreras were talking and joking the night of June 20, 2011, and went outside two or three times. He said he served Contreras five Miller Lite beers throughout the evening and he left by 11:30 p.m.

After learning of Burton’s killing, Martin said he contacted Maine State Police about a customer who resembled the description released by police of the suspect.

Defense attorney Christopher Berryment questioned the accuracy of Martin’s testimony about the time Contreras left the bar and the number of beers he was served.

He asked if Contreras appeared angry or made him feel uneasy.

Martin said no.

The state also called Contreras’ ex-wife, Amanda Pressey, and her father, Vern Pressey, to testify Wednesday.

Contreras and Pressey came to Maine in 2010 and lived with her father at 114 Pillsbury Lane, which is about two-tenths of a mile from Burton’s apartment.

Both said Contreras showed them a cut on the top of his hand the morning of June 21, 2011. Vern Pressey said he told Contreras he should go to the hospital for stitches, but he wouldn’t.

Contreras told Amanda he had cut his hand carving their initials into a tree, she said.

Both said he was intoxicated that night, but they could only smell alcohol, not marijuana.

When police knocked on their apartment door the next day, Amanda Pressey said she went to the door and Contreras went to their bedroom.

As she and her father learned more about Grace’s death and as police searched for a man with a cut on his hand, both said concerns grew about Contreras. They discussed it and Vern Pressey asked him if he killed Burton.

“‘No, I did not kill her. I would never do that,’” Pressey said he told them. They believed him, she said.

The couple married in August 2010 and were divorced this past January. Amanda told the court Contreras drank a lot but was never physically violent to her.

He was unhappy here and couldn’t find work, and he thought people were racist toward him, she said. Contreras was born in Guatemala but spent most of his life in Massachusetts.

That’s where he was arrested on Nov. 17, 2011, after his DNA matched that of blood samples found outside Burton’s apartment. Contreras moved back to Massachusetts about a month after the killing.

The trial continues Thursday before Justice Michaela Murphy, and is expected to last into next week.