Police yesterday investigated the slayings of two men in separate shootings in West Oak Lane and South Philadelphia.

In the first case, Martin Norcome, 30, was shot in the chest about 11 p.m. Monday during a robbery behind his home in the 7800 block of Michener Avenue, police said.

Norcome was taken to Albert Einstein Medical Center, where he died at 1:09 a.m. yesterday, police said.

Officials said that, in the second slaying, Montez Felder, 21, of the 2800 block of South Marshall Street, was shot in the head on the 2200 block of South Street about 12:43 a.m. yesterday.

Medics pronounced him dead 10 minutes later. Police were seeking a motive.

Court records show that Felder had a previous conviction for drug possession and had an outstanding bench warrant in an assault case.

The slayings raised to 31 the number of homicides this year in the city.

Police brass have noted that although homicides are ahead of last year's pace, there is a difference.

Unlike the same period in 2006, when about two-thirds of the homicides occurred outdoors, 16 of this year's slayings have been indoors and 15 outside.

Before the latest slayings, police said 10 of this year's homicides stemmed from arguments, six from robbery and three from domestic disputes. The primary cause of 10 others was undetermined.

Contact staff writer Joseph Gambardello at 215-854-2153

or jgambardello@phillynews.com.