The RCMP say they have new evidence in the case of pipeline bombings in British Columbia, after the arrest and release of convicted Alberta oilpatch vandal Wiebo Ludwig.

Ludwig taken into custody Friday by RCMP, and released Saturday morning. He was questioned in connection with a series of pipeline bombings targeting energy firm EnCana in B.C.

Ludwig walked out of the RCMP detachment in Grande Prairie, Alta., early Saturday, about 24 hours after dozens of RCMP officers descended on his farm to execute a search warrant.

"I've had quite the grilling," a shaken Ludwig said while leaving the detachment.

The person interviewing him was retired Mountie Don Adam, considered one of the best interrogators in the country, CTV News has learned. Adam headed up the Robert Pickton serial murders case.

Ludwig's lawyer, Paul Moreau, had said Friday that his client would be charged with extorting the Calgary-based firm.

On Saturday, RCMP said they had "reasonable and probable grounds" to make an arrest, but the B.C. Crown prosecutor's office didn't see sufficient evidence to lay charges.

"I don't know what has caused this, what appears to be a change of mind on the part of the RCMP," Moreau told CTV News Channel in a telephone interview from Edmonton. "Nor do I know whether they might change their minds back again."

Hours after Ludwig's release, RCMP released a statement saying the search of the man's property was still underway and charges could still be laid.

"Recently collected evidence will be submitted to Crown Counsel for their consideration," the statement read. "Discussions with B.C. Crown Counsel continue to determine what charges, if any, could apply."

When he arrived home at his farm, known as Trickle Creek, Ludwig told a waiting group of reporters that officers interrogated him for 10 hours Friday night, "five hours of which I shut down, but they kept talking."

"They still want to do a little bit of work before they get their forces together," Ludwig said.

On Friday, between 30 and 40 officers descended on Ludwig's farm outside of Hythe, Alta., which is about 25 kilometres east of the British Columbia border. Officers are expected to remain at the farm for another few days as their search warrant is good for five days.

The farm is about 325 hectares, meaning there is a lot of ground to cover for police.

RCMP Insp. Tim Shields said Saturday afternoon that police have new evidence in the case and will submit it to the Crown. However, Shields declined to say if the new evidence was garnered from the search of Ludwig's property.

"We're not about to say exactly what it was that we found and I'm not even necessarily saying that we found it on this particular property," Shields said.

Shields added that the RCMP had "reasonable and probable grounds" to make the arrest, but prosecutors did not deem the evidence sufficient to lay charges.

RCMP Supt. Lloyd Plante said Friday he could not comment on what officers were looking for or what information led them to Ludwig's farm.

However, family members told reporters the search warrant indicated investigators were on the hunt for specific writing utensils, blue and red ink, envelopes, stamps, computer equipment and dynamite.

In a statement issued Friday, Plante said "we have followed a trail of evidence that ultimately led to the execution of the search warrant."

He also called Ludwig's arrest a "significant development in the 15 month-long investigation into the bombings."

Letters added to mystery

In each incident, the bomber targeted the Calgary-based energy firm EnCana. At one point, someone claiming to be the bomber wrote a letter demanding that the company halt operations in the area.

In July, a second letter addressed to a local newspaper said that things "could get a lot worse" if EnCana refused to stop operating in the area.

The company had offered a $1-million reward for information leading to the conviction of anyone involved with the bombings. In its statement Saturday, the RCMP said the reward has not yet been claimed.

Ludwig was convicted in connection with two Alberta gas-well bombings that took place in 1998 and served 28 months in prison.

He has long claimed that oil and gas development near his land have harmed the health of his family and the animals on his farm.

"He was taking great affront to the fact that civilization began to find him with rapid oil and gas expansion around the farm in the early nineties," CTV's Rob Brown told News Channel from Grande Prairie on Saturday morning. "And that culminated in a series of explosions in and around his farm."

Despite having a rocky relationship with local law enforcement officials, Ludwig had been helping the RCMP investigate the Dawson Creek incidents.

Last fall, Ludwig wrote a public letter to the bomber in which he appealed for calm and called for an end to the bombings.

According to Moreau, Ludwig's arrest and subsequent release have left his client "confused and puzzled."

"I believe he remains very concerned about the situation," Moreau said. "In light of what has happened I'm not so sure that he is anxious anymore to assist the RCMP."

With files from The Canadian Press