Image copyright Bucks County District Attorney's Office Image caption The missing men. From left: Tom Meo, Dean Finocchiaro, Jimi Patrick, Mark Sturgis

The remains of one of four young men who went missing last week have been found on a Pennsylvania farm.

The grim discovery was unearthed in a "grave" along with other bodies on a 90-acre tract of land in suburban Philadelphia, said officials.

The remains belong to Dean Finocchiaro, 19 who disappeared last Friday, according to investigators.

Mark Sturgis, 22, and Tom Meo, 21, also vanished on Friday. Jimi Tar Patrick, 19, went missing two days earlier.

On Wednesday this week, authorities arrested the son of the owners of the Bucks County farm, 20-year-old Cosmo DiNardo.

Image copyright Bucks County District Attorney Image caption Cosmo DiNardo, whose parents own the farm

He is accused of trying to sell Mr Meo's 1996 Nissan Maxima for $500 (£390), a day after its owner was last seen.

A "life-saving" diabetic kit that Mr Meo requires was still inside the car, investigators said.

Prosecutors said homicide charges could follow for Mr DiNardo, whose bail was set at the unusually high amount of $5m in cash.

Officials described him as dangerous and said he has schizophrenia.

District Attorney Matthew Weintraub told a press conference early on Thursday morning: "There are additional human remains inside that grave.

"So this painstaking process will go on. We're not done yet.

"This is a homicide, make no mistake about it. We just don't know how many homicides, we have yet to know the answer to that question," the District Attorney said.

Image copyright ABC Image caption It may take days to sift through the property, investigators say

He added: "We had cadaver dogs, and I don't understand the science behind it, but those dogs could smell these poor boys twelve-and-a-half feet below the ground."

The relationship between the four missing men is not clear.

Mr Sturgis' father told the Associated Press he employs his son and Mr Meo, a talented wrestler, in construction, and that Mr Finocchiaro is a mutual friend of theirs.

Mr Patrick and Mr DiNardo both attended the same high school, a year apart, reports the Philadelphia Inquirer.

A lawyer for the DiNardo family released a statement saying: "As parents, Mr and Mrs Dinardo sympathise with the parents and families of the missing young men and they are co-operating in every way possible with the investigation being conducted by law enforcement."