BOSTON (WHDH) -- The MBTA wants to help riders track trouble. A new smartphone app is aimed at getting riders to report suspicious activity.

The free app was unveiled on Monday. It is part of the T’s “See Something, Say Something” campaign that encourages riders to report anything suspicious.

“Most importantly they can take a picture of what they see out there,” said Chief Paul MacMillan of the MBTA transit police. “It’s for suspicious behavior, unusual behavior they might see and report directly to the transit police.”

The app provides two options for contacting authorities -- through a text message or a photo. A separate, "Call Transit Police" button allows users to speak directly to police.

Users can also send tips anonymously. This feature was added because police said they’ve heard passengers say they’re often afraid to speak up when they see a problem.

“They can sit on the train and text us and send us a picture of what’s going on and people around them may not know how they’re communicating with,” said MacMillan.

Riders agree that the subtle way to inform authorities of the activity is helpful. But, other riders believe that people might report harmless inconveniences.

Either way, transit police say they want to give the T’s 1.3 million riders another tool for safety. They said they are not worried about false reports and sometimes even minor details could be extremely important.

“If it’s reported to us we’ll thoroughly investigate it to see if it’s legitimate and if it is we’ll take appropriate action. If it’s not, we’ll vet it out that way.

The free app was released for the iPhone on Monday. The app will be available on android-powered smartphones in July.

It cost $50,000 to create the app, which was paid for by a grant from Homeland Security.

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