LTSS WHEN RPTR TURNED A COMMUTER BE02 INSIDE AND ACROSS THE DEP TRACK OF A C172. CONFLICT ALERT ACTIVATED AFTER THE ACFT HAD PASSED. THE BE02 REMAINED ON THE RPTR'S FREQ DURING THIS MANEUVER. OPERROR.

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THE CESSNA HAD DEPARTED THE LNK ARPT ON A 140 DEG HDG AND THE BEECH HAD BEEN CLRED FOR TKOF ON THE PARALLEL RWY WITH A HDG OF 170 DEGS ASSIGNED. DURING MY POS RELIEF BRIEFING WHICH HAPPENED AFTER THE ABOVE; I WAS ADVISED THAT THE CESSNA MAY BE TURNED BACK INTO MY DEP CORRIDOR. I TOOK THE POS AND IT APPEARED TO ME THAT THE CESSNA WAS DRIFTING BACK TOWARD THE W. THE BEECH HAD NOT STARTED DEP ROLL YET; SO I CALLED THE E DEP CTLR AND ASKED FOR A 90 DEG HDG ON THE BEECH SO AS TO PASS N OF THE CESSNA. IT WAS APPROVED BY THE E CTLR. BY THIS TIME THE BEECH HAD STARTED HIS TKOF ROLL; SO I WAITED UNTIL HE WAS AIRBORNE AND GAVE HIM THE NEW HDG AND ASKED HIM TO START THE TURN AS SOON AS FEASIBLE AND ISSUED TFC ON THE CESSNA AT HIS 10 O'CLOCK AND 3 MI. I CONTINUED TO WATCH THE SIT AND OBSERVED THE RATE OF TURN WAS NOT TO MY LIKING AND TURNED THE BEECH TO 60 DEGS TO INCREASE HIS RATE OF TURN TO OBTAIN THE DIVERGENCE I NEEDED. I BELIEVE I HAD THE PROPER DIVERGENCE; BUT THE CONFLICT ALERT WENT OFF. MY PERCEPTION THAT THE CESSNA WAS DRIFTING BACK INTO THE DEP PATH OF THE BEECH; AND HAVING WORKED WITH THIS PARTICULAR COMMUTER FOR THE PAST 8 YRS I BELIEVED THAT THEY WOULD START THEIR TURN TO THE E IMMEDIATELY OFF THE RWY AS THEY ALWAYS HAVE; LED ME INTO A SIT I HAD TO WATCH MORE CLOSELY THAN SHOULD HAVE BEEN NECESSARY. IN THE FUTURE I WILL DEFINITELY USE A DIFFERENT ACTION TO FACILITATE THE SEPARATION OF ACFT. IN HINDSIGHT A TURN TO THE SW FOR THE BEECH WOULD HAVE BEEN A BETTER IDEA. I BELIEVE MY INTENT TO GET THE BEECH COMMUTER ON COURSE AS SOON AS POSSIBLE ADDED TO MY ORIGINAL DECISION TO TURN THE BEECH TO THE E INSTEAD OF TO THE W. I WOULD LIKE TO ADD; THAT AS USUAL THE CONFLICT ALERT DID NOT GO OFF UNTIL AFTER THE ACFT HAD PASSED.