A hammer attack on an elderly man at his front door in Sydney was followed hours later by a second assault nearby, with detectives releasing footage of a man they believe could help their investigation.
Two men, aged 75 and 71, were injured in separate attacks less than 14 hours apart in Sydney’s north west, and investigators believe the incidents were random.

The first attack happened about 9pm on Tuesday at a home on Doomben Ave, Eastwood.
Emergency crews were called after a 75-year-old man was struck in the face with a hammer when he opened his front door after someone knocked.
Paramedics treated the man at the scene before taking him to Royal North Shore Hospital in a stable condition.
A second man was attacked shortly before 7am on Wednesday at a park on the corner of Blaxland Rd and Doomben Ave, also in Eastwood.
The 71-year-old was hit several times in the face and head with a hammer before he was taken to Royal North Shore Hospital in a serious but stable condition.
Specialist officers examined both scenes as detectives worked to piece together what happened.

On Wednesday, police released CCTV footage of a man who they believe may be able to assist with inquiries.
The footage appears to show the man bent over and looking into the Woolworths bag he is carrying. The top portion of his body is out of frame.
What appears to be a hammer is briefly visible in his hand before he runs off.
He is described as being of caucasian appearance, in his 30s, about 170cm tall, with light brown hair.
In the footage, he is wearing a dark tracksuit and carrying a green Woolworths bag.
Investigators are urging anyone who was in the area at the time, or who has dashcam, mobile phone or CCTV footage, to come forward.
They are particularly keen to hear from drivers who travelled along Blaxland Rd between 6.30am and 7.10am on Wednesday.
Anyone with information is urged to contact Ryde Police Station or Crime Stoppers.
