An RCMP dog searches Wiebo Ludwig's farm near the entrance to the property. (Jimmy Jeong/Canadian Press)Anti-oilpatch activist Wiebo Ludwig says police interrogated him for 10 hours after arresting him as part of an investigation into a series of gas pipeline bombings in British Columbia.

The Alberta farmer was arrested Friday and held overnight in jail as police continued to gather evidence, but he was released early Saturday without any charges being laid.

A day after his release, Ludwig told CBC News that police tried a couple of tactics to get answers.

"They talked about having my DNA. It was about a 10-hour drilling to try to break my spirit and compare me to Nelson Mandela and all that kind of ego-tripping, you know, hoping that I would have enough ego to think, 'Yeah, I'm just like Nelson Mandela,' and cough up like he did just before he got 27 years."

Ludwig said he was indifferent when he heard that police thought he was a suspect in the bombings near Dawson Creek, B.C. He said he was more concerned with the "real criminals" in the oil and gas industry.

He denied being the B.C. pipeline bomber, but described himself to CBC News as "a leading spirit" in the fight against the industry.

"I have talked to many people at Tomslake, [B.C.], and I have encouraged that they not just lie down under it, so I have been involved in different ways. I've not placed any bombs, in case that's what's you're wondering."

RCMP continue to search the property of Wiebo Ludwig, who was arrested Friday but released early Saturday without being charged. (CBC)Ludwig has long argued that oil and gas projects near his farm have hurt the health of his family and livestock. He spent 19 months in prison in the late 1990s for bombings against sour gas wells in northwestern Alberta.

His latest comments were made as about 60 officers worked for a second full day on his 325-hectare farm, scouring homes, barns and outbuildings on the property, which is 400 kilometres northwest of Edmonton.

The search also involves sniffer dogs and a helicopter. In video taken by the Ludwig family and obtained by the CBC, officers can be seen rifling through kitchen cupboards and walking upstairs.

The RCMP, acting on a five-day search warrant, raided Ludwig's property near Hythe, Alta., on Friday. At the same time, they took the activist into custody after he agreed to meet with an investigator about 60 kilometres away in Grande Prairie.

Police are investigating six natural gas pipeline bombings in B.C. since October 2008, along with letters demanding that Calgary-based energy company EnCana cease operations.

Warrant lists writing materials, explosives

The police search warrant lists pens, writing paper, recording equipment and explosives as items investigators are looking for, according to Ludwig's lawyer, Paul Moreau.

"Police are also looking for a boot with a tread that they saw at the site of one of the bombings in B.C.," the CBC's Briar Stewart said Sunday.

Moreau said on Saturday that he wasn't sure what changed for investigators since they decided to arrest his client. He said first, they informed Ludwig that he would be charged with extortion of EnCana, but then he was released without any charges being laid.

"Clearly the police felt they had reasonable and probable grounds at that point. He was in custody for about 24 hours in RCMP cells in Grande Prairie," Moreau said.

"And this morning they've released him without charging him. So apparently they must feel they no longer have those reasonable and probable grounds."

On Saturday, police said any decision to lay charges is up to Crown prosecutors in B.C., who have indicated there isn't enough evidence at this point to lay charges.

RCMP Insp. Tim Shields said police believe they're on the right track and have found new information this weekend. He would not elaborate what the new evidence is or whether it was found on Ludwig's farm, which is home to dozens of people.

Shields reiterated Sunday that police have unearthed new evidence to hand over to prosecutors in B.C.

"We have obtained new evidence within the last 48 hours that we will be submitting to Crown counsel and we believe that this evidence is significant," he said.

"Ultimately, it will be Crown counsel's decision as to whether or not a criminal charge is justified."

With files from The Canadian Press