Investigators identified her as 26-year-old Danielle Mehlman of Bensalem.
The man suspected of her murder, Pawan Kumar, 26, of the 3000 block of Naamans Road at the Stratford Apartments, remains on the loose.
He has been charged with first-degree murder and possession of a deadly weapon during the commission of a felony.
Anyone who knows the whereabouts of Kumar is asked to contact Detective Chambers at 302-856-5850 ext. 206 or the Delaware Crime Stoppers at 1-800-TIP-3333.
Police released a surveillance picture of a man, now identified as Kumar, on Monday evening.
Mehlman body was found by housekeeping staff at 11:00 a.m. Monday in a room on the first floor of the Atlantic Oceanside Motel in the 1700 block of Coastal Highway.
Dewey Beach is a popular summertime destination between Rehoboth Beach and Bethany Beach along Delaware's Atlantic shore.