Police in Arizona have arrested a teenager suspected of beating and fatally stabbing a 54-year-old he met on the net.

Mark G. Woodland was found dead at his apartment in northeast Pheonix, after he was seen walking home with 19-year-old Tommy Reed [pictured], who is now facing a second-degree murder charge, reported the Arizona Republic.

The last thing Woodland’s flatmate heard from him was a text message asking for privacy so he could be alone with the teen, who he made contact with on an undisclosed website.

Reed was arrested after police checked Woodland’s phone messages, and witnesses came forward with information about seeing him in his final hours.

Arizona’s media initially reported that the men met on Grindr, but the city’s police now say their continuing investigation has revealed that another web-based social network was used.

Boy assaulted, Grindr blamed

Meanwhile, police in Canada are blaming Grindr for a sexual assault on a 15-year-old boy.

A 54-year-old Vancouver man has been charged with sexual assault, sexual interference and invitation to sexual touching, reports the Vancouverite.

Police in the city have cautioned parents to take notice of what they’re doing with their phones.

“Advances in technology and social networking make it easier for our children to come into contact with individuals who may try to harm them or take advantage of them,” says a cop on the case.

Apple says Grindr is designed for guys aged 17 and over only.