Collocations for intruder - noun

unwanted, unwelcome
masked

apprehend, catch
detect, disturb (BrE), find
He found a masked intruder in the kitchen.

chase away, deter, discourage, keep away, keep out
Dogs can deter unwelcome intruders.

tackle (BrE)
He was stabbed when he tackled an intruder armed with a knife.

repel
Staff were instructed to repel intruders with physical force, if need be.

break into, force their way into (esp. BrE)
Intruders had forced their way into the house.

alarm, alert

against intruders
security measures against intruders