An Anderson man has admitted that he built explosives and placed them along roads near his home in January and February, including one that detonated inside a wicker basket to injure a father, federal prosecutors announced Monday.

Wesley Dallas Ayers, 27, pledged allegiance to the Islamic State in letters and warned of a jihad, according to investigators' testimony in an earlier hearing. Now, after pleading guilty to using weapons of mass destruction, Ayers faces at least 20 years in prison and a $250,000 fine.

He could face life imprisonment, according to the U.S. Attorney's Office.

Ayers has not yet been sentenced, and a date for the sentencing has not yet been set, Lance Crick, a spokesman for the U.S. Attorney's Office, told the Independent Mail.

One of Ayers' homemade explosives was discovered Jan. 30 near the intersection of Travis and Martin roads. In that case, a 49-year-old man found a wicker basket and heard something in it hissing, he told investigators. When he opened the basket, the device detonated and he suffered a minor leg injury, according to the Anderson County Sheriff's Office. His 14-year-old daughter was with him, and her screams were captured on home video and audio surveillance footage.

Previously:Anderson man indicted on explosives-related charges

Along with the basket was a drawing that depicted the White House with flames superimposed over it, FBI agent Ted Socha testified at a preliminary hearing for Ayers last March. Included were Arabic references to the "mother of Islam" and a drawing depicting Osama bin Laden in front of the White House, Socha said.

Other "hoax boxes" that didn't contain live devices were discovered in early February, Socha said. One of the boxes included a three-page typed letter that said the incident with the wicker basket in January "was only the start" of what the community could expect, and that "gifts" would keep coming "until the Islamic State and flag are above all others," Socha testified.

One device was a teddy bear that had been wired so its eyes glowed in the dark.

Investigators said Ayers has a tattoo that is nearly identical to the stuffed animal, including the glowing eyes.

In all, Ayers admitted that he built and placed three explosive devices in Anderson County during a month-long period last winter. He has pleaded guilty to using, attempting to use and threatening to use weapons of mass destruction; possession and discharge of a firearm in furtherance of a violent crime; and using an explosive device during the commission of a felony, according to the U.S. Attorney's Office.

Socha testified a behavioral analysis of Ayers indicates that the 27-year-old could be fueled by methamphetamine and violence. Socha said meth, the drug that would keep Ayers awake at night, allowed him to work in an old shed on Travis Road under the cover of darkness mixing his own concoctions of gunpowder and crafting homemade explosives.