A man believed to be the serial knife-wielding robber targeting stores in Nassau and Suffolk counties struck a Ronkonkoma store in broad daylight Sunday, police say.

This time, the knifepoint bandit left The Barn on Hawkins Avenue with an undisclosed amount of cash shortly before noon Sunday. There are signs hanging in the store that say there is never more than $50 kept in the register.

No one was hurt.

It marks the 17th similar crime involving a man with a knife or machete in hand, police say. The same suspect is believed to have struck 10 locations in Nassau and seven in Suffolk.

The robberies have taken place as far west as Lynbrook and as far east as Ronkonkoma. Sunday's robbery also marks the third such crime in Ronkonkoma since February.  

The suspect has been caught on surveillance video in previous incidents, but police have said that poor video quality has made him difficult to identify.  

Footage from The Barn's eight security cameras was handed over to police, according to a manager.

"It was very simple, just, 'Give me the money,'" says manager Winston Thomas, retelling the account of a female employee who was working alone at the time of the robbery.

Suffolk and Nassau police are offering a $10,000 reward for information that leads to an arrest.

Anyone with information is asked to call Suffolk Crime Stoppers at 1-800-220-TIPS or Nassau Crime Stoppers at 1-800-244-TIPS.