The stepbrother of a 12-year-old girl who died with her 16-year-old cousin in a Guthrie Center fire last May has been charged with two counts of murder.

Patrick Ryan Thompson, 26, of Ames, also faces two counts of attempted murder and a count of arson. He is being held in the Guthrie County Jail.

Cousins Shakiah Cockerham, 16, and Melanie Paige Exline, 12, died in the May 15 house fire that also left their uncle, 54-year-old William Long III, with severe burns on his upper body.

The girls' grandmother, Shirley Exline, 74, suffered minor injuries in the blaze.

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Thompson's stepfather, James Hubert Exline Jr., 46, also was arrested Wednesday on two counts of sexual abuse against his daughter, Paige.

Before the fire, 19-year-old Noah Exline, of Jefferson, had been charged with seven counts of felony sex abuse against Paige, his sister. Noah Exline is Thompson's stepbrother and roommate.

Investigators said in May they were investigating whether there was a connection between the sex abuse case and the fire.

Although Wednesday's arrests were announced during the same news conference, Guthrie Center Sheriff Marty Arganbright would not confirm whether the arson and sexual abuse charges are connected.

“It’s why we’ve been doing an ongoing investigation with this case,” Arganbright said when asked whether the fire might have been set to thwart the sexual assault investigation.

Shirley Exline told The Register in May that she believed the arson was related to an ongoing sexual abuse case involving her family.

She alleged the fire was set to silence Paige from testifying about family abuse in a hearing that was set for later that month.

The two girls were living with Shirley Exline at the time of the arson. Shakiah had lived with her grandmother since she was a baby.

Exline said she was fighting to gain custody of Paige, with a hearing set for four days after the fire.

“I’m overjoyed they got them off the street,” Shirley Exline said Wednesday about the arrests.

Long, the girls' uncle, is out of the hospital but remains "in constant pain," Shirley Exline said Wednesday.

James Exline Jr. is on Iowa’s sex offender registry. He was convicted of sex abuse and lascivious acts against two girls in 2009, court records show.

One of the victims in the 2009 conviction was younger than 13.