NEW HAVEN, Conn. — Attorneys defending a Connecticut man charged with killing a former Slippery Rock woman and her two daughters in a 2007 home invasion in which the house was doused in gas and set on fire have begun their defense by trying to show he could have had gasoline on his clothes from a roofing job.

An attorney for Joshua Komisarjevsky called a contractor today in New Haven Superior Court who testified that Komisarjevsky was doing a roofing job the day before the crime.

The contractor, Michael Ranno, said he wasn’t sure if Komisarjevsky was cleaning tools or using gas power, but a roofing company representative said roofers use gas-powered machines and flammable products.

Komisarjevsky’s attorneys blame his co-defendant for pouring the gas.

Komisarjevsky faces a possible death sentence if convicted.

The woman who was killed, Jennifer Hawke-Petit, spent part of her elementary school years in Slippery Rock.

She and the man who later would become her husband met while they worked at Children’s Hospital in Pittsburgh.