Gurnee police arrest armed robbery suspect

With the help of a Lake County sheriff's dog, Gurnee officers tracked down an armed robber who tried to escape by jumping from the second-floor of an apartment Friday, authorities said.

Marshon D. Knox, 21, of Zion is charged with armed robbery and unlawful use of a weapon.

The victim was attempting to sell a cellphone through an online app. When the two met for the exchange about 11:30 a.m. on the 200 block of O'Plaine Road, Knox displayed a gun, took the phone and ran toward a nearby apartment complex, police said.

When officers attempted to make contact at the apartment, Knox jumped from a second-story window and ran, police said.