"This is a man suffering," Joshua Glotzer, a lawyer for Rainer Klaus Reinscheid, told Orange County Superior Court Judge Gregg Prickett.
The judge continued the sentencing hearing until Thursday, The Orange County Register reported.
Reinscheid, a 49-year-old associate professor in the departments of pharmaceutical sciences, pharmacology and molecular biology and biochemistry at the University of California, Irvine, had apologized to the court Tuesday and asked for mercy, the newspaper said.
"I lost my son, and then I lost myself," Reinscheid told Prickett. "My grief was overwhelming. It felt like the end of the world to me."
Reinscheid's 14-year-old son took his own life in March 2012 and Reinscheid went on to set five fires later that year and allegedly sent ominous emails of plans for sexual assaults and mass killings, though he wasn't charged concerning the emails.
The academician faces three to 18 years in state prison, with prosecutors seeking the maximum, KNBC-TV, Los Angeles, reported.
"I would like to take this opportunity to apologize," Reinscheid said Tuesday.
"I can promise you that when released, I will not be a threat to harm any person or property."
Others, however, asked the court to impose a stiff sentence.
"We need you to help us return to work with less fear each day," one said.