I think Robert Kirkland was
Miranda Martins' s boyfriend (Lorelei 's sister), that 's why he asked Lennon
if he recognized him. After knowing Lennon was involved in Miranda 's murder,
he killed Lennon for revenge, and didn’t asked who Red John was because it was
useless.
And that's why Kirkland is behind
Patrick's footsteps, he has not the intelligence of Patrick, Kirkland will wait for Patrick to catch
Red John because HE want s to kill him first.