A San Clemente man will face sentencing in federal court Monday after pleading guilty to drug trafficking and tax evasion charges in May; he ran several marijuana stores, one of which was the Safe Harbor Collective in Dana Point.

Authorities say the shops earned him about $25 million over six years. John Melvin Walker, 56, pleaded guilty to a count of conspiring to distribute more than a ton of marijuana and to a count of tax evasion, according to Thom Mrozek of the U.S. Attorney's Office.

Walker faces a federal prison term from 10 years to more than 20 years, according to the plea bargain, Mrozek said. Walker agreed to not argue for less than 15 years in prison, according to the deal. Walker was among 14 people indicted by a federal grand jury in October in the alleged conspiracy.

The dispensaries operated by Walker were identified as Alternative Herbal Health in Long Beach, Safe Harbor Collective in Dana Point, Garden Grove Alternative Care in Garden Grove, Santa Ana Superior Care in Santa Ana, Belmont Shore Natural Care in Long Beach, Santa Fe Compassionate Health Care in Santa Fe Springs, Costa Mesa Patients Association in Costa Mesa, the Whittier Collective in Whittier, and APCC in San Juan Capistrano. Walker ordered managers of his marijuana businesses to routinely shred records, so he could avoid paying taxes, according to Mrozek.

Walker, for example, admitted he netted $11.4 million in 2009 while only reporting $200,180 in income and that he owed $2,656 in taxes to the IRS, according to the plea deal. Walker, however, owed $944,133 in taxes in 2009, Mrozek said.

Walker agreed to pay $2.4 million in federal taxes and $1.8 million in state taxes. He also will give up $25 million from the marijuana sales, which includes assets such as his San Clemente home worth $1.7 million, multiple mobile homes in Mammoth Lakes, rental properties in Long Beach and his interest in two strip clubs, according to Mrozek.

Walker faces extra years in prison because authorities guns similar to a AK-47 in one of Walker's defendant's stash houses. The other defendants arrested or identified in October are: