HACKENSACK, N.J. -- A jury convicted a Florida man Friday of murdering his former son-in-law, rejecting the man's defense that he was too fat to have run up and down a flight of stairs to commit the crime and make a quick getaway.

Edward Ates looked down and shook his head in court as he was found guilty of murder and weapons counts for killing Paul Duncsak, who was shot six times at his home in Ramsey, about 25 miles northwest of New York.

Ates' "too fat to kill" defense provided an angle to the trial that attracted attention from the news media but didn't sway the jury of eight women and four men, who reached a verdict on their second day of deliberations after a six-week trial.

Some of Duncsak's family members cried softly after the verdict was read. Ate's 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."

Ates had argued he didn't have the energy to accurately shoot Duncsak from a perch on the staircase at Duncsak's home in August 2006. He was 62 years old, 5-feet-8 and 285 pounds at the time of the murder.

Assistant Bergen County Prosecutor Wayne Mello termed Ates' defense "nonsense" and credited dogged work by investigators, particularly Det. Sgt. Russ Christiana, that built a circumstantial case around cell phone records and computer forensics.

"This was a complicated case, and it was good old-fashioned police work combined with new technology," Mello said.

Prosecutors contended Ates drove from Florida to New Jersey, climbed a staircase and shot the 40-year-old Duncsak, a pharmaceutical executive who was embroiled in a bitter custody dispute with Ates' daughter after their divorce.

Ates then drove 21 hours to his mother's house in Louisiana, prosecutors said. The last evidence the jurors reviewed in court on Friday was videotaped testimony from Ates' sister in which she admitted that she lied to authorities about when he arrived in Louisiana, per his request.

Brenda Ates has already pleaded guilty to hindering prosecution and is not expected to get prison time when she is sentenced, Bergen County Prosecutor John Molinelli said Friday. Molinelli is proceeding with hindering charges against Ates' wife and mother.

Prosecutors presented evidence at trial to show Ates bought books detailing how to build a gun silencer, did Internet searches on how to pick locks and how to commit the perfect murder.

Ates, meanwhile, testified at the trial that he often needed to take breaks while driving, implying that he wasn't capable of making the drive to Louisiana.

In addition, Ates' doctor testified that bounding up the stairs, as the killer was thought to have done, would have caused Ates to become short of breath and shake, making it difficult to keep his wrist straight enough to accurately fire a gun at someone from a distance.

Duncsak's mother, Sophia, has said Ates became vengeful toward her son after Paul Duncsak refused to give Ates money to keep Ates' struggling golf course in Okeechobee, Fla., afloat.

State Superior Court Judge Harry G. Carroll set sentencing for Dec. 17 and revoked Ates' bail.