An up-and-coming member of the Long Island Democratic party mysteriously disappeared nearly a week ago leaving his clothes and phone on a beach.

Nassau County police say Petros Krommidas, 29, was wearing a camouflage print sweatshirt and gray sweatpants when he went missing on April 24 at Baldwin not far from New York’s JFK airport.

His family says he arrived in the area at 10:30 p.m. and might have gone into the water for a late-night swim.

The ocean water temperature is around 50 degrees, according to a surfing website that tracks water conditions. Unconsciousness is possible in about 30 minutes in water between 40 to 50 degrees. The family says Mr. Krommidas is in great shape and not a stranger to cold water training.

The family says he parked his car by the Allegria Hotel at Long Beach, locked his car, took a towel, and walked onto the beach.

His family says he exercised on the beach many times in the past and they reported him missing the next day saying, “It is completely out of character for him not to respond.”

“Every pair of eyes helps. Every step along the beach matters. Thank you for being part of bringing Petey home,” the family said in a Facebook plea.

Police have not been able to locate him and have not speculated on the possibility he went into the water on his own.

Mr. Krommidas is running for a seat in Nassau County’s legislature. The Long Island native graduated from Columbia University and worked at Morgan Stanley and Sageview Capital before going into politics. He started as a Democratic party clerk and then became a field organizer and served on the New York elections board at Nassau County.

He is running to represent the 4th District at Nassau County. Republican Patrick Mullaney currently holds the seat.

The County Democratic chairman, Jay Jacobs, told WNBC-TV that “Petros is a bright, driven young man who has been a strong voice for Democratic values. He is well respected by the community and represents the very best of our next generation of leaders.”

The day before he disappeared he spoke to the county’s Young Democrats meeting. “Thank you to the Nassau County Young Democrats for having me — always great to be with such a thoughtful, engaged group committed to making a difference in our community,” Mr. Krommidas said on his campaign Facebook page.

Mr. Krommidas is described as being 6-foot-2 and 230 pounds with brown hair and brown eyes.