UNIONDALE - Four suspects who allegedly carried out a string of armed robberies in Nassau County have been arrested, police say.

The seven attacks occurred over the last month in Hempstead, Baldwin, Rockville Centre and Uniondale.

The suspects have been identified as Juan Vallecillo, his wife Cecilia Vallecillo, Jaime Machado, and Henry Hernandez.

Police say they used a knife and a realistic-looking toy gun to hold up several businesses. A delivery truck driver was also robbed.

The arrests came after a joint investigation by Hempstead and Nassau police departments.

The four were arraigned in court on robbery charges Saturday.