Salem Police Officers Mike Verrocchi and Paul Benoit joined the caravan, and the Salem Police Department posted a photo of them on Twitter. Salem Police also posted a message on Twitter, saying "Happy Birthday 7th birthday Tyler from SPD... Get well soon!!!"
In 2010, Tyler fought leukemia and in 2012, was considered cancer free. But in November of 2013, there was a string of bad headaches and his mother took him to the hospital. Blood tests showed that the cancer had come back.
Tyler's mom started a Facebook campaign to collect cards from police and firefighters, but the birthday surprise went viral and ballooned into Thursday's much larger effort.