The evidence given in his own defence by a Whitehorse man accused of assaulting his girlfriend and her four-year-old son was "inconsistent", "perplexing" and ultimately, insufficient, a Yukon judge decided Thursday.

Kevin Grunerud was charged with nine counts ranging from mischief to uttering death threats to assault with a weapon.

The charges stem from two incidents: one in March 2007, the other in November.

Both times, Grunderud turned up at his partner's house smelling of alcohol, she told the court. When she asked him to leave, things got out of control.

The first time, Grunderud took a sledgehammer to her front door after she locked him out and blocked the door with two kitchen chairs, Yukon Supreme Court was told.

Once he got into the house, the court heard, he knocked over the television and DVD player, then used the hammer to smash her cell phone so hard that he busted a hole right through the floor of her trailer.

By that time, the woman said, she had locked herself in the bathroom, the door of which he destroyed.

The RCMP arrived just as he was entering the bathroom, sledgehammer held over his head, threatening to strike.

Grunerud told a slightly different story.

He said he was just trying to get in to retreive his things, and the door wasn't blocked.

She turned over the TV and he broke her cell phone and the bathroom door in retribution, he told the court.

She wasn't in the bathroom when he did it and he never threatened her life, he said.

But Justice Leigh Gower wasn't buying it. The evidence given by the RCMP officer who arrived on the scene, and the photographs taken by investigators, all support the woman's story, not Grunerud's, the judge said Thursday.

"I do not believe the evidence of Mr. Grunerud where that conflicts with that of (the plaintiff)," Gower said.

The judge found Grunerud guilty of seven of the nine charges against him.

A charge of unlawful confinement was dismissed for lack of evidence.

A charge of dangerous driving was stayed because Grunerud was found guilty of using his vehicle to assault his former girlfriend, a heavier charge relating to the same incident.

Grunderud will return to court for sentencing on Feb. 19.

He will have served nearly 15 months by that time, which will count as 22 months toward his final sentence.