Lawyers for a man accused of murdering four women in a night of mayhem in Texas claim their client was suffering from low sodium levels in the brain when he committed the killings.

Erbie Bowser, 48, was responsible for two separate shootings in Dallas and DeSoto in August 2013. His estranged wife and girlfriend and their respective daughters were all killed.

On Monday (1 May ) Bowser pleaded not guilty in court as defence lawyers showed testimony claiming he had a shrunken hippocampus which had been caused by concussion when playing American football as a youth.

The defence also claimed he suffered Post Traumatic Stress Disorder (PTSD) from his time in the military, although he didn't see active service and was discharged in 2000 for being overweight.

According to the New York Daily News, prosecutors say Boswer's low sodium levels may have been caused by prescription drugs he was given after committing the killings. Neurological experts also disagreed on whether the low sodium levels and brain injures were enough to classify him insane.

'Gentle giant with dark side'

At 6ft 7in, Bowser was known as a gentle giant who taught special education and performed for the Dallas Mavericks' dance troupe, the ManiAACs. However, prosecutors claim he also had a dark side and threatened his wife, Zina, and her children when she filed for divorce.

On the night of 7 August 2013, the prosecution allege Bowser shot dead his girlfriend, Toya Smith, 43, and her daughter, Tasmia Allen, 17. Toya's son, 14, and a 17-year-old were wounded in the incident in southwest Dallas.

It is alleged Bowser then drove to his ex-wife Zina's house, blowing in the door with a grenade then killing her and her daughter, Neima Williams, 28. Her sons, aged 11 and 13, were wounded in the same incident before Bowser ran out of ammunition. If convicted, he faces the death penalty.

Erbie Boswer Texas murder suspect
Erbie Bowser is accused of the killing of 4 women in one night in August 2013 Dallas County Jail