A man who accidentally shot and killed his girlfriend in Oak Hill on Sunday night was trying to warn nearby target shooters because the woman was worried about her cats getting hurt, family members said on Monday.

"It was an accident and it all happened because my sister-in-law was worried about her cats," said Vicky L. McGee-Gregg in a telephone interview.

[READ: Volusia deputies investigating fatal shooting in Oak Hill]

Volusia County sheriff's deputies said the accidental shooting occurred at a tent in the woods near 232 North Brooks Circle around 5:05 p.m. Investigators said Dawn M. Schaefer, 53, was accidentally shot by her longtime boyfriend, Andrew Louis McGee, 49, when he slipped while holding a shotgun.

"They've been together for 23 years so my brother is taking it pretty rough," McGee-Gregg said.

According to investigators McGee reported he heard gunshots in the area and came out of the tent to fire a warning shot in response to those gunshots but slipped and accidentally shot Schaefer with an old, poorly functioning shotgun.

The incident remains under investigation and no charges have been filed, said sheriff's spokesman Andrew Gant.

Andrew McGee and Schaefer have been homeless for some time and relocated less than a year ago to his best friend's property. The couple moved to that location after they and other homeless people were evicted from a wooded property near Port Orange and New Smyrna Beach, his sister said.

But her brother's homelessness is by choice and lives in the woods because he likes his privacy, McGee-Gregg said.

"Their homelessness is not because they don't have an income," McGee-Gregg said. "They choose to live that way, in a tent."

Andrew McGee is a roofer and Schaefer, who once worked at a bar in Edgewater, was no longer working. She stayed at her home taking care of her pet Chihuahuas and her cats, McGee-Gregg said.

On Sunday, Andrew McGee had just come home from work and learned some boys were target shooting on the other side of the property.

So, Andrew McGee grabbed a shotgun with the intention of going outside to fire a warning shot but tripped, his sister said.

"As he was getting out, there is a rip at the bottom of the tent door and it wrapped around his foot and he tripped and fell and the gun went off," McGee-Gregg said. "It shot Dawn in the leg and hit a major artery."

Her brother tried to call 9-1-1 but the cellphone signal was poor. The calls kept dropping. So he went to the main house for help. After a 9-1-1 call was made, Andrew McGee went looking for a deputy and emergency workers.

In the meantime, a niece and his mother went to the scene and tried putting a tourniquet on Schaefer's leg to stop the bleeding.

"By the time my brother got back with the sheriff deputy and the medical professionals, it was too late," McGee-Gregg said. "Dawn had bled to death."