2 charged in killings of missing Pennsylvania men.
Meo's girlfriend told investigators that she had been texting with him on Friday until just before 7 p.m.
DiNardo had been arrested earlier this week on an unrelated firearms charge from February, for allegedly possessing a shotgun despite an involuntary commitment for mental illness.
DiNardo was jailed earlier Wednesday in lieu of $5 million bail for allegedly stealing and trying to sell the vehicle another of the missing men, 21-year-old Thomas Meo.
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Patrick was shot to death by DiNardo on July 5 as the two were alone on the farm, according to the affadavit.
The Bucks County district attorney planned to hold a news conference on Friday afternoon (Saturday morning NZ Time) to report on all the latest developments.
Data from a police license plate reader captured DiNardo's pickup and Meo's auto driving in Solebury Township within seconds of each other at 7:49 p.m. Friday, court documents said.
Cosmo DiNardo's lawyer said his "very emotional" client is ready to plead guilty to first-degree murder.
Amid a search for the men, investigators have focused on the Dinardo property in Solebury Township.
County District Attorney Matthew Weintraub has repeatedly stated that DiNardo is a person of interest - and not a suspect - in the disappearance of Meo, Mark Sturgis, Dean Finocchiaro and Jimi Taro Patrick.
DiNardo, who was named as a person of interest, was arrested Wednesday for stealing the vehicle of Meo.
DiNardo's parents, Antonio and Sandra DiNardo, own the farm in upper Bucks County, a bucolic area with rolling hillsides, new housing developments and historic sites. Lang told ABC 6 that DiNardo has "deep remorse" for his actions.
Weintraub also noted that Meo, a diabetic, appeared to have left his insulin in the auto - something his family said he would never do.
Police say the Loyola University Maryland student, 19, also didn't show up for work. For example, one of the men, Jimi Patrick, had once gone to school years ago with DiNardo, a diagnosed schizophrenic, and was his Facebook friend.
The son of the owners of the property where the remains were found was arrested. They shot and killed Finocchiaro and then placed him in a metal tank that he referred to as the pig roaster, Dinardo said, according to the criminal complaint.