A Waterloo woman has been arrested for allegedly stabbing her boyfriend in the back, according to the Waterloo Cedar Falls Courier. 19 year old Natalie Calderon is accused of stabbing Isaac Sommer in the back sometime after 4:00 a.m. Tuesday as Sommer attempted to leave to go back to his home. Police said the wound did not appear to be life threatening. Calderon is already awaiting trial for Burglary after allegedly crawling through a window to assault two people earlier this month.