A jury yesterday found Blenheim teenager Thomas Ewan Patterson not guilty of a series of assaults, after a teenage party turned sour at Whites Bay, near Rarangi.

Mr Patterson, 19, denied assaulting a woman, assault and assault with intent to injure on February 26 last year.

The jury took half an hour to return its verdict.

Crown prosecutor Mark O'Donoghue said Mr Patterson assaulted three teenagers Courtney Stewart, Tom Knowles and William Murray when he became angry after being "kicked in the nuts".

Miss Stewart had accidentally kicked Mr Patterson in the testicles while "play-fighting", prompting him to chase her and push her to the ground, Mr O'Donoghue said.

Mr Patterson had punched Mr Knowles and Mr Murray when they intervened, with Mr Murray also put in a headlock, which restricted his breathing, he said.

However, defence witness Matthew Ham told jurors yesterday Miss Stewart kicked Mr Patterson with force and without warning after he told her and other girls who were "being a nuisance" to go away.

Mr Ham did not see why Miss Stewart fell over, but said Mr Patterson did not hit either Mr Knowles or Mr Murray because he and another friend, Michael Washington, were holding Mr Patterson's arms.

Mr Patterson reacted in self-defence when Mr Murray grabbed him and put a closed fist against his throat, Mr Ham said.

Mr Washington, in written evidence, said Miss Stewart fell because she stopped suddenly and Mr Patterson, who was chasing her, crashed into her.

He did not see Mr Patterson punch Mr Knowles or Mr Murray.

In closing, Mr O'Donoghue said Mr Patterson had said he would never hit a woman, but that comment was made when he was sober.

"The people involved [at the party] are probably all good people, but someone here has had too much to drink and ... started behaving like a psycho."

Even Mr Washington came under verbal attack from Mr Patterson when he pulled him away from the scene.

"Anyone that stood in his way that night, Tom Patterson wasn't having any of it."

Defence counsel Nikki Utting urged the jury to be careful when considering Miss Stewart's evidence.

She had said twice that people had been hit at the party when she had only heard that from others.

"I suggest Miss Stewart has [also] tried to downplay her role. She said her and Mr Patterson were playfighting [when he was kicked in the testicles]. No-one else saw this."

All the Crown witnesses were affected by alcohol, while Mr Ham and Mr Washington were sober, Ms Utting said.

"Yes, he was angry. Yes, he was verbally abusing people. But he didn't hit anyone."