Hardly an hour goes by without Thomas Serafin or one of his cyber-sleuths checking what eBay has to offer.

They're not hunting for bargains and never place a bid. Their interest is bone shards, bits of wizened flesh and a contemporary twist on the sacred and the profane: How the ancient trade in the most coveted religious relics has moved into the global flea market of online bidding.

"You can find bone fragments supposedly from St. Augustine being hawked on the Internet along with trinkets and antiques. There is something very wrong here," said Serafin, a professional photographer and Catholic activist based in Los Angeles, who has led an expanding campaign since the late 1990s to block the online sale of objects purported to contain the remains of Christian saints.

Last month, Serafin's group, the International Crusade for Holy Relics, opened a new front that's truly worthy of a David and Goliath metaphor: a call to boycott eBay.

It seeks to pressure the world's largest online auction site to close alleged loopholes used to bypass its ban on allowing bids for human remains.

Hani Durzy, spokesman for eBay, said the company, based in San Jose, Calif., is "very willing to reopen talks" with Serafin's group about its concerns after discussions broke off about a year ago.

"As far as the boycott, well, we've really seen no impact to speak of," said Durzy. "We don't know if it's even still in place."

But Serafin said the symbolism is what's important.

"Yes, it's just a blip on the screen," he said. "But we want to make a point. They are taking the same position as Judas. They are selling out the church."

Interest in religious patrimony of all types — from icons to stained glass — has soared in recent years, along with the blockbuster novel "The Da Vinci Code," the Christian-themed "Left Behind" series and major museum exhibits devoted to art and spirituality. At the same time, a flood of ecclesiastical items has entered mainstream antiquarian markets from once-flourishing churches that were closed because of shrinking congregations or population shifts away from older city neighborhoods.

But the sale of so-called "first-class relics" — bone, flesh, hair, nails and fragments of other body parts — remains a murky subculture, one that's increasingly shifting from the back rooms of dealers' shops to the Web's worldwide mall.

Dozens of religious items are on eBay at any time. Most are ordinary objects such as icons, medals or prayer cards. But Serafin believes the strongest interest is for the first-class relics, which he says has accounted for up to 40 percent of the eBay relic listings at times.

"This is where the real action is," he said. "This is where our fight is."