Mercanti arrested over home invasion

Their ordeal only ended when police officers allegedly wrestled the Finks motorcycle gang member to the ground and took him into custody.

The 44-year-old remains in Sir Charles Gairdner Hospital this morning, where he is being guarded by armed police.

Police have charged Mr Mercanti with an act intended to cause grievous bodily harm, three counts of aggravated assault occasioning bodily harm, aggravated indecent assault over an unrelated matter, trespass and damage.

Mr Mercanti, a former Coffin Cheater whose decision to join the Finks has caused violence between the two gangs, was released from prison in August after paying a $4000 bond to be of good behaviour for two years.

He had been jailed for causing grievous bodily harm in a bar room brawl in Northbridge in 2007.

In the aftermath of today's bizarre incident, police from the gang crime squad raided Mr Mercanti's Duncraig home, only 500m from the scene of the attempted home invasion in Plumosa Mews.

It is alleged they found drugs and ammunition.

Mr Mercanti, who was described as being "agitated" when he was taken to hospital by St John Ambulance officers, is believed to have only recently returned from a Finks national run in Queensland.

The middle-aged couple, who did not want to be named, said they were woken about 4am by a man banging on their front door.

Switching on the outside lights, they could see a big man in a sleeveless shirt.

The female resident said they had called police and, while waiting for help, heard the man crash into their backyard.

She said he had probably jumped on their neighbour's gate and then climbed over the side fence into their property.

The resident said the man had then taken a lump of concrete from their wall and used it to smash repeatedly on a glass sliding door.

"We were terrified," she said. "We turned on the lights but that didn't stop him."

She said she did not know Mr Mercanti and did not know whether he was trying to hide or had mistaken the house for his own.

The couple were shocked to learn of his bikie connections.

"If he thought it was his house, I don't know what he would have done if he'd managed to get in and then not recognised us," she said.

"The door isn't broken but there are pieces of concrete and blood stuck to the glass."

The resident said she believed Mr Mercanti had cut himself when he climbed over the fence.

There was blood in the backyard and he had pulled down the washing line and knocked over rosebushes.

It is understood other residents in the street had also been woken by a man ringing their doorbell just a few minutes earlier.

The couple said police had arrived in less than 10 minutes, though it had seemed longer.

They had "wrestled him to the ground" and told him to behave, the female resident said.