Investigators from the Counter Narcotics Alliance seized as much as 7,000 pounds of marijuana south of Downtown Thursday morning and arrested four people on drug charges, officials said. Authorities estimated the wholesale value of the marijuana at $500 per pound, which means the bust could have a value of $3.5 million. Members of the multi- agency Counter Narcotics Alliance raided Bearing-Belt & Chain Inc., 430 W. 22nd St., at about 8:30 a.m. and seized an estimated 5,000 pounds of marijuana, said Lt. Kelly J. Lane of the Tucson Police Department. Earlier that day, around 6 a.m., police officers pulled over...