CHARLOTTE, N.Y. -- The search for the Perinton couple missing since the end of January continued Sunday in the waters of the Genesee River.

Monroe County Sheriff's Office and Rochester Police Department crews used boats and scuba teams to comb through the waters around the Rochester Marina for Robert and his wife Mary Ross.

They used underwater sonar equipment to search the area, which was the last known location where the couple's cell phone pinged near Lake Avenue in Charlotte on January 31.

No clues were found by the time they exited the river.

Authorities tell us that Robert, who was diagnosed with stage 4cancer last year, was last seen at a medical appointment on January 30.

A concerned social worker notified authorities after he missed subsequent appointments.

Mary was last heard from on January 29 in a phone conversation with her son. He has since traveled here from Boston to assist in the search along with a family friend.

"It's been stressful, it's been stressful. We get ups and downs. We are starting to hearing of some hits on some sightings and they're all being searched out but until right now nothing has been coming forward. So we’re just waiting and the waiting is the worst part,” said Tom Lockwood, Robert’s friend.

"You know we're here and it's kind of tricky because you don't want to find anything and yet you want to find something because we just want them home. So you know it's just a little tough,” said Bob Ross.

There has been no word yet on when the search for the couple will continue.

The two own a white 2017 Kia Sorrento with New York plates reading “BLUSTERY”.

Anyone with information is asked to call 911.