SUNBURY, Pa. -

It isn't that the man had done anything wrong to infuriate Elytte Barbour and his wife.

The couple -- married three weeks -- just wanted to kill someone together, police said.

And Troy LaFerrara, 42, happened to be the unlucky one.

The Barbours are accused of luring LaFerrara through a "companionship" ad on Craigslist, and stabbing and strangling him to death.

Barbour told police he and his wife had tried to kill others. But the plans didn't work out.

"This happened to be one that worked," Sunbury Police Chief Steve Mazzeo told CNN.

The ad

LaFerrara's body was found in the backyard of a home in Sunbury, Northumberland Co., a small city about 100 miles northwest of Philadelphia, on November 12.

He had been stabbed 20 times and strangled, police said.

The last number dialed on his cell phone led police to the Barbours.

At first, the wife, Miranda Barbour, 18, denied knowing the victim. But presented with more and more evidence that police had gathered, she confessed.

According to the police affidavit, this is what happened:

Miranda Barbour told police she would use Craigslist to meet men -- "men who wanted companionship," and were willing to pay her for it.

On November 11, she met LaFerrara at a mall, picked him up in her red Honda CR-V and drove to Sunbury.

Elytte Barbour was hiding under a blanket in the back seat, he said. The couple had agreed on a pre-arranged signal so that he would know when "it was time to kill the victim."

The death

After driving for a while, Miranda Barbour pulled over. LaFerrara reached over and began touching her, she said.

She then took a knife from between the front seats and stabbed him, she said. Once, twice, three times.

She told police she doesn't remember how long she went on.

LaFerrara tried to fight her, but couldn't. Elytte Barbour had tied a cable cord around his neck to hold his head back.

As LaFerrara fought, Elytte Barbour said he held tight.

The discovery

While they drove around looking for an an out-of-the-way spot to dump the victim, LaFerrara was still alive.

He was "choking and gasping for air," Miranda Barbour told police. But soon, his breathing stopped.

The couple dumped LaFerrara's body by the back garage of a house in Sunbury -- which is where resident Brittany Settler discovered it the next morning.