Demetrio Armando Ramirez, 19, of Redlands is suspected of stealing the teenage boy's cellphone at a bus stop near the intersection of Orange Street and Colton Avenue around 8 a.m.
Investigators with the Redlands Police Department developed leads to identify the suspect. Officers say they went to the 900 block of Alta Street on Friday and arrested Ramirez as he was leaving his home.
Ramirez was booked into the Central Detention Center in San Bernardino on suspicion of robbery, criminal threats and a parole violation.
Police say they recovered pieces from the destroyed iPhone at the suspect's home, and the knife used in the robbery was located behind a business near the bus stop. The police department is replacing the teen's iPhone using a portion of a 2010 Justice Assistance Grant designed to help crime victims.
Anyone with additional information about this case was asked to contact the Redlands Police Department at (909) 798-7681.