DUNDEE, Mich. -

A 3 1/2-year-old boy in southeastern Michigan died after picking up a gun that was left on the floor and shooting himself in the head, police said Monday.

The gun belonged to a man who was staying with Damon Holbrook's family, Dundee police Sgt. Tom Redmond said.

"He was negligent in securing the gun and (not) unloading the gun and leaving it accessible to a small child," Redmond said.

Gun owner Joshua Greenhill, 30, was remorseful but has been charged with manslaughter with gross negligence, the sergeant said.

"He had just arrived home from work. He had a pistol license," Redmond said. "He left the portable case on the bedroom closet floor and walked out of the bedroom and into the kitchen. ... Whenever there's kids, you should always unload the weapon."

The child went into the room and found the gun which had a bullet in the chamber and he pulled the trigger.

Damon was pronounced dead Sunday at a hospital in Ann Arbor. There were five other people in the home, including Damon's father.

Greenhill was charged with careless discharge of a firearm, which carries a maximum of 2 years in prison and a $2,000 fine

Dundee Police Chief David Yuhl anticipates more serious charges will follow.

Greenhill was release on personal bond and his pre-trial is set for Sept. 4.