Over a two-day period starting last Wednesday night, four young men in Bucks County, a wealthy Philadelphia suburb where new construction meets large estates, disappeared.

The first to vanish, Jimi Taro Patrick, 19, was last seen around 6 p.m. on Wednesday in Newtown Township, Pa., and did not show up for work the next day, the authorities said.

On Friday around 6 p.m., Mark Sturgis, 22, told his father he was going to meet up with his longtime best friend, Tom Meo, 21, and that they would be ready for their construction jobs the next morning. They did not show up, and their cellphones went straight to voice mail.

Dean Finocchiaro, 18, was last seen about 6:30 p.m. on Friday in Middletown Township.

In the hours after the four men disappeared, the police departments and the district attorney’s office in Bucks County — where violent crime is considered rare — cast a wide net, searching throughout the county and requesting the public’s help on social media. On Saturday afternoon, the authorities got a break: Mr. Finocchiaro’s cellphone was tracked to a vast farm off a country road in Solebury Township.