Police in Vancouver are crediting a Good Samaritan for halting a sledgehammer attack on an elderly man in the city's notorious Downtown Eastside Tuesday afternoon.

The 72-year-old Vancouver resident was returning to his car near the intersection of Main and Hastings streets after having lunch around 3 p.m. when he was attacked in an alley.

"Suddenly out of nowhere a man approached him from behind and struck him repeatedly with [a] sledgehammer," Const. Jana McGuinness told reporters from the alley at a press conference Thursday morning.

"Allegedly he struck him numerous times in an attempt to rob him."

A woman passing by heard the commotion and ran into the alley to help, throwing herself between the assailant and the elderly man.

"As he was being pummeled with the sledgehammer she put her body in between and the suspect then raised the sledgehammer as if to hit her but he didn't," McGuinness said.

The suspect then ran out of the lane.

The woman stayed with the senior until an ambulance arrived. He suffered a serious head injury that required upwards of a dozen staples to close.

"He was bleeding profusely from large wound in his head," McGuinness said.

The woman was able to provide a detailed suspect description to police. Vancouver Police Beat Enforcement Teams immediately began a street sweep of the area and local businesses.

With the assistance of surveillance video in the area, two VPD members recognized the suspect and named him. He was taken into custody around 8 a.m. Wednesday.

Danny Joseph Jordan, 46, of Vancouver is charged with assault with a weapon and robbery. He appeared in Vancouver Provincial Court Thursday.

Police say Jordan has a "gamut" of offences dating back to 1981.

The victim is recovering at home with his family.

McGuinness said the role of the Good Samaritan cannot be underestimated.

"What that woman did is nothing short of brave," she said. "If she hadn't intervened this could have been tragic and ended very differently."

Police say violent crimes against seniors have risen in the troubled neighbourhood in the last five years.

Despite projects targeting offenders, the department says it sees many robberies by thieves who see seniors – many who have lived in the area for decades -- as a way to get quick cash for drugs.

"Unfortunately there are people in the area with substance abuse issues and are looking for quick cash and a senior is a soft and easy target," McGuinness said.

"It can end tragically when they're assaulted."

Sgt. Mark Steinkampf says more than 50 per cent of Vancouver's violent crime happens in the Downtown Eastside -- much of it against seniors.

He says elderly victims are less likely to come forward to authorities and are often victimized by assaults much more than the average person.

"Their bones are broken easier and their injuries are more significant and it takes them more time to heal," he said.

This is the second attack on a senior in the area in as many weeks.

On March 16, a man with no fixed address was charged after allegedly beating an 81-year-old with a beer mug in a pub in the 200-block of East Hastings Street.

Steinkampf said police take violent crimes targeting the elderly very seriously.

"We all get old, we all have parents or friends that are old and we can put ourselves in that situation," he said. "It's sad."