"Please don't let it be a Muslim" has overnight become a widely-shared thought among Muslims online.
A Libyan named Hend Amry was the first to tweet "Please don't be a 'Muslim.'" Her message was retweeted nearly 300 times and forwarded by well-known journalists and writers.
"Was this thought crossing your mind today?" asked the Muslim Public Affairs Council on their Facebook page, as the Washington Post reports. "Seems like it was for many Muslims."
Soon after the Boston attack, the group released a statement: "MPAC condemns heinous terrorist attack. Our thoughts and prayers are with all those in Boston." MPAC's president said that such statements usually don't get media attention, giving the impression that Muslims haven't condemned the attacks.
Fears were heightened after the New York Post reported that a Saudi national was in custody," he added.
Muslim anxiety probably isn't helped by comments like that from Eric Rush, a pundit for the ultra-conservative site Infowars. "Let's bring more Saudis in without screening them...#bostonmarathon" he tweeted. "Are you ALREADY BLAMING MUSLIMS??" another Twitter user replied. "Yes, they're evil. Let's kill them all," Rush responded, claiming later that it was a black joke.