Detectives are urging people to ensure their homes are properly locked up at night after a number of suspicious incidents in the Clay Cross area.
The reminder comes after several incidents in recent weeks where people have woken up to find an intruder in their house.
In the most recent incident, which took place at about 5.20am on Monday, an elderly woman was woken up when a man walked into her room.
He fled the property, in Handley Lane, Handley, and the victim was left shaken but uninjured.
Another incident occurred at a house in Bevan Road, Danesmoor, in the early hours of Saturday.
A woman was awoken by a disturbance and saw a man running out of her house.
Detectives are investigating these and other incidents and are urging people to make sure their doors and windows are properly locked at night and to consider installing house alarms and security lights.
Witnesses or anyone with information should call Derbyshire police on 101 or Crimestopers on 080 555 111.