HACKENSACK, N.J. — A jury rejected a Florida man's claims that he was too fat to have run up and down a flight of stairs and killed his former son-in-law, convicting him Friday of murder.

Edward Ates looked down and shook his head in court as he was found guilty of murder and weapons counts for killing Paul Duncsak, a 40-year-old pharmaceutical executive who was shot six times in August 2006.

The panel of eight women and four men issued its verdict on its second day of deliberations after a trial that lasted more than a month.

Ates, 62, had argued he didn't have the energy to accurately shoot Duncsak from a perch on the staircase at Duncsak's home in Ramsey, about 25 miles northwest of New York, and make a quick getaway to Louisiana. Ates weighed 285 pounds at the time.

Defense attorney Walter Lesnevich said they would immediately appeal the verdict.

Prosecutors claimed Ates drove from his home in Fort Pierce, Fla., to Duncsak's $1.1 million home in Ramsey, about 25 miles northwest of Manhattan, in August 2006. Once there, they said he climbed a staircase and shot him as he returned from work. At the time, the victim and Ates' daughter were involved in a bitter custody dispute after their divorce.

Police quickly suspected Ates and found him 24 hours later at his mother's home in Sibley, La.

During the trial, Lesnevich said his client was in such bad shape that he could not have pulled off the shooting or made such a quick getaway, driving 21 hours drive to Louisiana in order to create an alibi as prosecutors claimed he did.

"Look at him," Lesnevich told jurors, noting that Ates was 60 pounds heavier at the time of the crime.

Ates took the stand in his own defense during the trial, saying he had no reason to want Duncsak dead. But he didn't delve much into his weight.

Some of Duncsak's family members cried softly after the verdict was read. Ates' wife, Dottie, sobbed in the gallery as he was handcuffed and led away by court deputies.

"It doesn't bring him back, but at least he won't get away with it," said Duncsak's sister-in-law, Barbara Duncsak. "It's satisfying. It was a long time coming."