The Pennsylvania State Police suggested Monday that the Montgomery County 21-year-old Matthew R. Royer, who has been missing since leaving Rhode Island Thursday, might have decided on his own to detour from returning home to Skippack Township.

"While it may be a voluntary move on Matthew's part, we are still expending all resources in this investigation to locate Matthew," said Trooper Morgan Crummy, a spokeswoman at the State Police's Skippack station.

As that possibility took shape in what remains a murky situation, his mother made a tearful plea for her son to contact his parents.

"Matthew if you can hear this - no matter what the circumstances are - your friends and your family, we all love you," his mother said Monday afternoon at a news conference in front of the state police station in Skippack. "We're here for you. Please contact us, call home. We will come anywhere, anyplace, anytime for you. We are here for you. We love you and miss you."

Authorities are poring through dozens of leads on the whereabouts of Matthew Royer, a Perkiomen Valley High School graduate, who texted his mother on Thursday that he was leaving his apartment in Narragansett, R.I., to return home for the summer.

His parents, who live in Collegeville, were away over the weekend, but rushed home when they learned their son hadn't shown up for his job at the Skippack Golf Club.

At that point, they began tracing his path from Rhode Island and learned he last was seen on a video from a security camera at 2:05 a.m. Friday, at a Sunoco station on Route 100, about a 30-minute drive from his home.

State Police said this morning that a witness who learned of Matthew Royer's disappearance through the media, reported seeing his silver 2008 Chevrolet Cobalt 11 hours after the previous sighting, at the intersections of Routes 501 and 422 in Lebanon County, more than an hour from his home.

Crummy said later today that the police still were trying to verify that report and "dozens" of other leads they had gotten since publicizing that Royer was disappeared.

Royer lived about a 20-minute drive from the University of Rhode Island. Earlier media reports said Royer was in the doctor-of-pharmacy program there, but he dropped out at the end of the fall 2012 term, university spokeswoman Linda Acciardo said.

He did not take classes in the spring 2013 term, though he still is registered as a student at the school, Acciardo said. He began attending the university in the fall of 2009.

"We have been in touch with the family" and have spoken with his parents several times, she said. "We're deeply concerned about his welfare and are looking for a good outcome to what appears to be a difficult situation."

Acciardo added that staff in the pharmacy program who knew Royer said he was quiet, likable, and hardworking.

Waiting to hear what has happened with their son is difficult, Randy Royer, Matthew's father, said earlier Monday.

"It has been four days, and we're physically and mentally exhausted," Royer said. "Just get the word out to find our child."

Royer is 6-foot-1, weighs 160 pounds, and has brown hair and blue eyes. He last was seen wearing a dark-green golf shirt, khaki shorts, flip-flops and a baseball cap. His silver Cobalt has Pennsylvania license plate GZR 9059.

The Narragansett Police Department and Skippack Station of the Pennsylvania State Police are jointly looking for Royer.

Anyone with information about him can call the Skippack state police station at 610-584-1250.