Police today arrested a 17-year-old boy suspected of being one of four teenagers involved in an early morning robbery spree last month.

With today's arrest, Kalihi Crime Reduction Unit officers have arrested three of the four suspects, including an 18-year-old man who allegedly threatened employees of businesses in Waipahu and McCully with a knife during holdups on the morning of Oct. 25. The third suspect arrested is a boy, 17.

The suspect at large is a 16-year-old boy, who allegedly served as a lookout in the Waipahu and McCully robbers.

The spree started in Waipahu at 4:15 a.m. and continued in McCully at 5:25 a.m., where the suspects unsuccessfully tried to force an employee to open a safe. The spree ended in Waikiki at 6:20 a.m. when two of the suspects, 18 and 16, grabbed the purses of two women waiting at a busstop. The women, ages 39 and 36, were dragged 20-30 feet while hanging on to their purses.

The suspects fled in a waiting sports utility vehicle with one purse.