Crowley, a freshman at Iona Preparatory School, was last seen on Friday, possibly at the Metro-North train station in White Plains, New York, according to LoHud.com, a local Gannett-owned publication. He is 5 feet 10 inches, weighs 150 pounds and was wearing a bright blue Florida Gators short-sleeve T-shirt.
In an email to friends, his parents, Peter and Gretchen Crowley, said the teen was not feeling well before he disappeared and is in a fragile state.
In addition to alerting the police about their son's disappearance, they have mobilized volunteers to post fliers in Westchester, Connecticut, Manhattan and the Bronx, a family friend told LoHud.com.
They have also set up an email account, email@example.com, to receive tips about their son's whereabouts.
On Twitter, efforts to help find Crowley were tweeted under the #FindPierce hashtag.
My birthday is tomorrow and my biggest birthday wish is for my friend Pierce Crowley to return home safely...We miss you kid #FindPierce, tweeted @AnttCee.
David Chong, police commissioner of White Plains, said he is concerned about Crowley's disappearance, although he doesn't suspect any foul play, adding that he wanted to let the teen know that everyone wants him back home safely, reported myfoxny.com.
Anyone with information about Crowley's whereabouts is asked to call the White Plains police at 914-422-6111, stated LoHud.com.
I'm wearing a necklace he gave me and I'm not taking it off until he comes home. Neither Peter or I are the same without Pierce. He is the heart of us and huge void that we want found safe and sound soon, said Crowley's mother.