05/11/2012 11:41 am ET Updated May 11, 2012

Kevin Bristol's Family Says Man Was 'A Very Loving Father And That Michael Was His Entire World' (VIDEO)

Police are now saying that it's likely Thornton resident Kevin Bristol shot himself after killing his 4-year-old son early Tuesday morning, but the family tells 9News there was no indication anything was wrong.

"Anybody who has ever known my brother Kevin knows he's a very loving father and that Michael was his entire world," Kristen Schwartz, Bristol's younger sister told the news station. The family added that Bristol had lots of plans for the future.

Of the hundreds of photos still available on Bristol's Facebook page, almost half of them are of Michael.

Police say that Bristol's wife Carmen Bristol was home when the shooting occurred and found the two in a back room each with a single gunshot wound to the head. The father was listed as being in critical condition until he passed away Wednesday morning while his son Michael was pronounced dead at the hospital.

Media reports indicate that no one even heard a gunshot, though investigators say they confiscated two guns from the home. One of them, a .22-caliber rifle, was used in the shootings.

According to the Denver Post, there were only three people in the home at the time of the shooting and the couple were having marital issues.

As a memorial began to spring up outside the home, a friend of Kevin Bristol's told 7News that Bristol had told him he and his wife were breaking up and that he had a lot of work to do to get custody of his son.