A Jefferson County judge has formally charged Kelvin Roy with murder.

Roy is accused of causing a collision that killed a Vidor teen last Friday night.

Roy's niece says the key witness against her uncle is lying.

Angela Bell admits her uncle uses drugs and sells marijuana. She said she believes he should face the consequences for the collision that claimed the life of Lexy Bertrand.

However, Bell says her uncle might be guilty of manslaughter, not murder.

Orange County authorities have charged Roy with murder because of what Taralynn Brown told them.

Brown was in the car with Roy. She says he was trying to kill her and himself, and that he intentionally crashed into the van in which Lexy was a passenger.

Brown also claims Roy was high.

12News obtained the probable cause affidavit in which Brown tells Vidor Police Detective James Blankenship that she could see the stopped minivan that Lexy was in stopped at the traffic light.

The affidavit goes on to say, "Ms. Brown said she was screaming at the defendant (Roy), "You're going to hit the car!" and he replied, "(Expletive), I'm gonna kill both of us". Ms Brown said the defendant accelerated the car and as he did she could actually hear the motor getting louder...Ms. Brown stated the defendant could have avoided the crash, but chose not to."

But Bell says Brown is lying to get herself out of trouble. She says Brown should be held accountable too because she knew about Roy's drug habits, and because the couple were in her car.

Bell says Brown could have prevented the tragedy.

She said, "Instead of her saying 'No Kelvin, give me the keys, or I'm going to call police, this car ain't moving', she got right in the car with him and rode with him knowing that he could have did something like that."

Another one of Roy's nieces, Audrey Lewis told us her uncle would not be charged with murder if it weren't for Brown's claims.

Lewis points to Tarrant County teen Ethan Couch, who was convicted of intoxication manslaughter for causing a wreck that killed four people, and Crystal Boyett of Kirbyville, who's charged with manslaughter for a wreck a week-and-a-half ago that claimed the lives of two sisters and an unborn child.

But she says because Brown claims Roy tried to kill her, police are pursuing the murder charge, and Lewis also says Brown is lying.

Bell says Brown should have been drug tested the night of the wreck.

But Vidor Police Chief Dave Shows says a blood sample was just taken from Roy, the driver.

Brown does have a prior conviction for marijuana possession, but Chief Shows says he has no reason to doubt her credibility.