GLENDALE, Colo. -- Glendale police are investigating whether an animal rights activist could be to blame for the arson at the Sheepskin Factory on Colorado Boulevard.

The building burned to the ground in April.

On June 15 an anonymous e-mail was sent to 7NEWS and the Glendale Police Department from someone who claims the fire was set to send a message in defense of the animals. This is the second tip police have received where an animal rights group took credit for the arson.

The tipster signs the note, "ALF Lone Wolf" and said he is also responsible for the fire at a leather factory in Salt Lake City in the first week of June. The note warns that "making a living from the use and abuse of animals will not be tolerated" and it mentions the Sheepskin Factory in Glendale.

"We treat it as a significant lead," said Victor Ross, Glendale's chief of police. "Whether it is a credible lead, we don't know yet."

Israel Dominguez, an employee of the Sheepskin Factory, said it is somewhat of a relief having someone take credit for the arson.

"I am sorry they feel like this," said Dominguez. "It is hard to stand up from this, but we have heart so we are going to continue."

But there is concern the new store, which opened just around the corner on Virginia Boulevard, may now be targeted.

"I am nervous," said Dominguez. "Maybe they will come back and hurt us again in retaliation."

7NEWS discovered that the Animal Liberation Front, or ALF, states on its website that arson is a tactic they use. In a YouTube posting, an unknown ALF members states that the fires are meant "to inflict economic damage to those who profit from the misery and exploitation of animals."

The Animal Liberation Front is aligned with the Earth Liberation Front, whose members were convicted in a 1998 fire at the Vail ski resort that did $12 million in damage. ALF is also connected to the arson of the lambskin processing plant in Greeley in 2002.

"Most of what [ALF does] is against the law, so we got to look at it," said Ross.

The Glendale Police Department is not alone in the investigation. The Bureau of Alcohol, Tobacco, Firearms and Explosives is working on the arson and Ross said the FBI may soon be getting involved.

So far there have been no arrests.