Beto O’Rourke ‘received threats via Facebook’ from mail-bombing suspect Cesar Sayoc

The Texas Democrat has been critical of Donald Trump in his Senate race

Texas Senate Democratic candidate Beto O'Rourke received threatening Facebook messages from pipe bomb package suspect Cesar Sayoc (AFP)

Texas Senate candidate Beto O’Rourke has allegedly received threats from Cesar Sayoc, the man suspected of mailing several pipe bombs to prominent Democrats and other critics of Donald Trump.

Campaign spokesperson Chris Evans told the Texas Tribune the candidate did not receive a suspicious package but “we received a threat via Facebook from that individual in April, a threat towards Beto, and we immediately reported it to the [US] Capitol police”.

Mr Evans added: “Then we turned over the message and the information and the threat to the FBI in July.”

Mr O’Rourke has been picking up steam as he challenges Republican incumbent Ted Cruz, raising millions more in campaign contributions in the past few months.

After Mr Sayoc was arrested in Plantation, Florida, a list of more than 100 potential targets was allegedly found among his possessions.

It is unclear at this time if Mr O’Rourke was on that list.

At least some of the messages to the Texas candidate included pictures of Mr O’Rourke’s family, his campaign said, and read: “Hug your loved ones every time you leave home. See you soon.”

The FBI sent agents to the current House Democrat’s office in El Paso, Texas, to check its mail in the wake of the string of suspicious packages.

Mr O’Rourke appeared undeterred however.

On the campaign trail, he told the newspaper: “We just got to continue to do our best to be good to one another, to try to lead by example....I feel safe in this state. I feel like we do right and good by one another when given the chance, and we’re going to continue to do that.”

Mr Sayoc has been accused by a state legislator of tracking him too.

“The guy was Googling me, stalking me, trying to find out stuff about me — coming up with my address at the Capitol and at home,” state House Democrat Poncho Nevárez said after he was also visited by the FBI last week.

Mr Nevarez confirmed his Texas Capitol office in Austin had received a package which triggered an evacuation.

Police investigated and cleared the package, saying there was no threat.

Mr Sayoc is suspected of sending up to 15 explosive devices or suspicious packages addressed to Bill and Hillary Clinton, Barack and Michelle Obama, Joe Biden, former US Attorney General Eric Holder, House Democrat Maxine Waters, Democratic Senators Kamala Harris and Cory Booker, former Director of National Intelligence James Clapper, former CIA Director John Brennan, billionaires and Democratic contributors George Soros and Tom Steyer, actor Robert DeNiro, and CNN.

Ms Waters and Mr Biden both received two packages.

Mr Sayoc has appeared in court, with another appearance set for later this week.

The packages also contained a return address for House Democrat from south Florida and former Democratic national chair Debbie Wasserman-Schultz.

All have been vocal critics of Mr Trump and the public targets of his criticism.