What were the driving forces behind Tamerlan and Dzhokhar Tsarnaev, the two men responsible for the Boston Marathon bombing? Take your pick: poverty, drugs, schizophrenia, history of violence in the family, and isolation as immigrants, according to a five-month long Boston Globe investigation published on Sunday. According to the paper, the Tsarnaev family did not emigrate to the U.S. for asylum, but rather were likely on the run from organized crime, which their father had crossed. Both the Tsarnaev parents received psychiatric help upon their arrival in the U.S. (and their father likely struggled with a form of post-traumatic stress disorder), but they never sought help for Tamerlan and instead directed him toward religion. Dzhokhar, meanwhile, was popular for his partying in college and his casual drug use, before falling under Tamerlan’s influence.