McKinney police arrested a third person Wednesday in connection with a burglary, house fire and manslaughter.
Smokey-Dawn Smith, 25, was arrested in Garland Wednesday for burglary of a habitation - a 2nd degree felony.
Police say Smith, along with Winfred Watkins and Christopher Graham, robbed a home on the 2000-block of Hillcrest on Oct. 26. During the course of that robbery, the house was set on fire and the son of the owner, Stephen Cummins, was killed.
Earlier in the week, officers from Dallas and McKinney worked with the U.S. Marshal's Joint East Texas task force to arrest Winfred Watkins and Christopher Graham.
Watkins is charged with burglary, and Graham faces charges of manslaughter, arson and burglary.
Police now believe the fire was set intentionally to cover-up Cummins' death.
"We're confident that the actions of Graham, on or about October 26th, 2011, precipitated the death of Stephen Cummins," McKinney police Assistant Chief Scott Brewer said.
Smith is being held at the Collin County Detention Center on $2,000 bond.