investigators checked a trash can at boston common following the stabbing of two park rangers .
evans said bodio hutchinson attacked the unarmed rangers in what the commissioner said was an unprovoked confrontation at about 4:30 p.m. evans said witnesses followed the suspect and provided cellphone video to police .
boston globe boston police chased bodio hutchinson , 34 , into the public garden , where they arrested him and fished a knife out of a nearby pond , officials said .
advertisement “ our prayers are with both of the rangers , ” said boston police commissioner william evans at a press conference tuesday night .
” authorities did not name the two men wounded rangers on boston common , the nation 's oldest public park .
he said a 23 and had just joined the force .
commissioner william evans said tuesday night that a 46 - year - old ranger sergeant is in surgery at massachusetts general hospital with life - threatening injuries .
before officers tackled him to the pavement , witnesses said hutchison faces attempted murder charges .
hutchinson was sitting on the soldiers and sailors monument statue in the common when the rangers , who were not armed , approached him , said .