The Irvine parents accused of planting drugs in the car of a PTA president and school volunteer -- who they reportedly believed had treated their son poorly -- pleaded not guilty Monday to charges related to conspiracy and false imprisonment. 

Kent Wycliff Easter, 38, and Jill Bjorkholm Easter, 39, are accused of plotting against school volunteer Kelli Peters.

The Easters believed that Peters had locked their son, then a first-grader, outside during an after school program and had said negative things about Jill Easter, The Times previously reported, citing court documents.

Just after midnight Feb. 16, 2011, Kent Easter allegedly drove to Peters' home and placed a bag of Vicodin, Percocet, marijuana and a used marijuana pipe behind the driver's seat of her unlocked car, authorities said.

Prosecutors said the father left the drugs in plain sight, easily visible from outside the vehicle. 

The next afternoon, officials said, Easter is accused of calling an Irvine police non-emergency line, giving authorities a false name and address. Officials alleged that the father told the dispatcher he was a concerned parent and had seen erratic driving near an elementary school.

He identified Peters by name and claimed to have witnessed her hiding a bag of drugs in her car. He then gave a description of the vehicle. 

Prosecutors allege that Easter remained in constant contact with his wife through calling and texting as their alleged plot unfolded. 

The Easters, both lawyers, each faces three charges: conspiracy to commit a crime, conspiracy to falsely charge or indict another of a crime and false imprisonment effected by violence, menace, fraud or deceit.