Police say the disappearance of a Springfield construction worker who went missing this summer is now considered suspicious.

Oscar Velasco Montano, who was 29 when he disappeared in July but would now be 30, was last at work on the 1800 block of International Drive in Tysons Corner on July 9.

Fairfax County police initially said the construction worker was believed to have left on his own, but authorities said this week his disappearance was not voluntary.

Officer Tawny Wright, a Fairfax police spokeswoman, said "there were certain details that have been uncovered recently" that have led investigators to call the disappearance suspicious. She would not elaborate on that evidence.

Wright said the length of time Montano has been missing also raised concerns about foul play.

"We're going into five months now and nobody's heard from him," she said. "That definitely contributed to the notion that he was involved in some type of crime."

Wright said police believe Montano was a victim and not involved in illegal activities.

Montano was heard leaving his home for work the morning he went missing and apparently completed his work day, his family has said. But he has not been seen or heard from since then.

His family reported him missing two days later, and a detective was assigned to the case the next week. Investigators have combed through security footage from near his work and interviewed friends, relatives and colleagues. Investigators are continuing to conduct interviews, Wright said.

More than 900 people have joined a Facebook group formed in an effort to seek answers about his disappearance.

Montano is described as a Hispanic man who is about 5 feet 6 inches tall and weighs 180 pounds. He has black hair and brown eyes.

Anyone who has information about this disappearance is asked to call Fairfax County police at 703-691-2131 or Crime Solver sat 866-411-TIPS (8477). Tipsters can also send a text message that reads "TIP187" plus the message to 274637.

ebabay@washingtonexaminer.com