BOSTON (AP) — An attorney for the Massachusetts man accused of sending letters with white powder to five people, including one to Donald Trump Jr., says his client will plead not guilty.

Attorney Scott Gleason says Daniel Frisiello (friz-ee-EHL'-oh) is "an overwhelmed young man."

A judge has ordered Frisiello held pending a detention hearing Monday.

Gleason says Frisiello has some "issues" and "difficulties" and has been on medication his entire life, but declined to elaborate.

Federal authorities say Frisiello sent five envelopes early last month that included threatening messages often containing profanities and white substances. The envelopes were postmarked in Boston. The white substance turned out to be nonhazardous.