A Chesterton man whose home in the Villages of Sand Creek police say was found full of hydroponically grown marijuana plants has pleaded guilty to the first count in a five-count indictment, the U.S. Attorney’s Office for the Northern District of Indiana said.

Alan Zimmerman, 43, pleaded guilty this week to knowingly possessing 100 or more marijuana plants with the intent to manufacture and distribute marijuana, the U.S. Attorney’s Office said.

The original indictment also charged Zimmerman with manufacturing and distributing marijuana; felon in possession of firearms; possessing a firearm in violation of the National Firearms Act; and possessing an unregistered firearm.

Under the plea agreement, the other four counts have been dismissed and Zimmerman is facing a mandatory minimum sentence of five years in prison and four years of supervised release. Also under that agreement, should Zimmerman qualify for enhanced penalties, the government will not seek to have them imposed.

The maximum sentence for the charge to which Zimmerman pleaded is 40 years in prison and a $2 million fine.

Zimmerman agreed as well to forfeit his “interest” in eight firearms found in his possession.

In July 2010, Zimmerman was taken into custody by the Porter County Drug Task Force (DTF) in a coordinated operation with the Porter County Sheriff’s Police, the Chesterton Police Department, the U.S. Drug Enforcement Administration, and the Cook County, Ill., Sheriff’s Police.

Recovered from Zimmerman’s home at 1759 Summerlin Court were around 763 marijuana plants in various stages of development, police said; 90 pounds of loose marijuana; numerous loaded semi-automatic military-style rifles, shotguns, handguns, and ammunition; several thousand pounds of hydroponic growing equipment; and numerous hypodermic syringes and needles.

Concurrent search warrants were executed at two other homes: one in Skokie, Ill., belonging to Zimmerman’s family, where more marijuana was recovered; the other in Berrien County, Mich., a $1.3 million estate owned by Zimmerman himself, police said.

Surveillance began on Zimmerman earlier in the summer last year after DTF received a tip from the Cook County HIDTA Task Force that Zimmerman was believed to be cultivating high-quality marijuana in Skokie and that he may be doing the same thing in Chesterton, police said. Energy records were subsequently obtained for Zimmerman’s home, indicating that while the previous owners had consumed an average of 1,200 kilowatts of electricity per month, Zimmerman was averaging 8,356 kilowatts, consistent with the energy consumption of grow lights, police said.

Zimmerman was initially charged in Porter Superior Court, then his case was transferred to the U.S. District Court for the Northern District of Indiana.