JACKSONVILLE, Fla. -- A grieving father took the stand and testified Friday about the last time he saw his twin sons alive; his ex-wife accused of murdering them.

Tommy Demeniuk was the first witness on the stand in the murder trial of his ex-wife Leslie Demeniuk.

According to police, Leslie Demeniuk shot her 4-year-old boys nearly five years ago.

During opening statements both sides painted two very different pictures. Prosecutors explained to the jury how Leslie Demeniuk got her gun, loaded it, and gunned down her sons as they watched TV. Defense attorneys described her as a troubled and depressed woman that was taking medications, which they said made her temporarily insane.

While on the stand, Tommy Demeniuk told the jury he tried to make their marriage work for the boys' sake, but after their birth, it was clear she cared more for her own desires than his or theirs. He said she drank too much, and after they separated, worried about his boys when they were with her.

"I didn't believe the lifestyle that she was leading was going to provide them with all their needs," said Tommy Demeniuk.

He told the jury she once said if the boys wanted to do drugs when they grew up, she would prefer they do drugs with her.

Under cross-examination, Tommy Demeniuk acknowledged Leslie was a good mother once, before her behavior changed.

Leslie Demeniuk's defense lawyers contended that when she shot and killed her sons, she was not in her right mind, and did what no sane mother would ever do.

Testimony is scheduled to resume Monday morning. The man who was dating Leslie Demeniuk at the time she killed her sons is expected to testify. He was the one that called 911 after walking in and seeing the two boys shot.