Police were able to use a victim’s iPhone to track down one of two men who robbed a Metra passenger at a South Side railroad station at gunpoint last week, prosecutors said today.

Dashawn Sharp, 18, was ordered held in lieu of $275,000 bail in a Cook County Bond Court hearing midday today after being charged with armed robbery, prosecutors said in a news release.

The robbery took place Sept. 11 in a stairwell at the Metra Station at 87th and Halsted streets. Sharp put a gun to a man’s chest as another robber searched the victim, taking his iPhone, wallet and keys, prosecutors said.

The man called police, and investigators were able to track the phone to a nearby cell phone store, where a clerk told them two people matching the robbers’ descriptions had tried to sell him an iPhone, but had been unable to unlock it.

Using surveillance video from the store, investigators were able to identify Sharp, of the 8400 block of South Sangamon Street, as a suspect, and Metra and Gresham District officers arrested him, prosecutors said.

Sharp is scheduled to appear in court again on Sept. 26. No information about the second suspect was available this afternoon.

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