A man was shot and killed in the backyard of his home in Philadelphia's Mill Creek neighborhood on Sunday night. Police said the man went to check out a noise and was shot several times.  

Police said just before 10:30 p.m., a man, a woman and two children were inside a home near 47th Street and Westminster Avenue when they heard a commotion in the backyard.  

When the 48-year-old man went outside to check it out, detectives said at least two gunmen shot the man several times at close range.

As police try to figure out a motive for the shooting, investigators are searching for any surveillance video to help them identify the suspects.

However, Philadelphia police inspector D F Pace said the home's surroundings are making it tough to figure out the gunmen's movements before and after the shooting.

"It's pretty wide open out here," Pace said. "There's no real fencing so you can access the home from a number of different locations, so that is adding to some questions we have as to what direction the gunmen came from and what direction they fled." 

Neither the woman nor the two children inside the home were injured in the shooting.

Detectives interviewed the woman, though they haven't detailed her relationship to the man.

Crime scene technicians found at least five shell casings from two different calibers of guns, including a rifle round.

Police are still trying to figure out a motive.