Where's lock coming from?

I have a never-ending job that waits on *DTAQ requests. That job calls an
RPGLE *PGM object. That RPG program runs in the same activation group as
the caller and ends with LR set to true. A few weeks back, I added a
static SQL DELETE (delete from TABLE where KEY like :local_variable).
Since then, we've had intermittent issues of these jobs holding locks on
TABLE. The program has no commitment control and "Close SQL cursor" is set
to *ENDMOD (although I don't think that applies here).

I'm trying to determine what's causing the lock and how to eliminate it.
Does anyone have any suggestions to try?

TIA