The FBI said the information was not provided to the bureau's Miami Field Office and no further investigation was conducted.
"Under established protocols, the information provided by the caller should have been assessed as a potential threat to life", the Federal Bureau of Investigation said in its statement on Friday.
Florida Governor Rick Scott said the FBI's failure was "unacceptable" and called for the resignation of FBI Director Christopher Wray.
In Parkland, Florida, students and family members gathered for a candlelight vigil Thursday night to mourn the 17 people who were killed on Wednesday in one of the deadliest school shootings in US history.
A flyer from the rally read "We are angry and we want safety", and presented a list of demands for lawmakers, including "extensive background checks", "elimination of the gun show loophole" and to "stop lobbying from the NRA".
Arguably the most memorable moment came when high school student Emma Gonzalez took to the podium and attacked the United States president and other politicians for accepting political donations from the National Rifle Association (NRA), a powerful gun rights lobby group.
US President Donald Trump announced Friday he was headed to Florida to meet with victims of the mass shooting that claimed 17 lives at a high school in Parkland.
Some political leaders including Trump have said mental illness prompted the shooting.
Broward County Sheriff Scott Israel has also said his office received more than 20 calls about Cruz in the past few years.
It is one of many student-led protests amassing support on social media in the wake of Wednesday's attack.
Saturday's rally coincided with a gun show in Florida.
The massacre has raised concerns about potential lapses in school security and stirred the ongoing U.S. debate pitting proponents of tougher restrictions on firearms against advocates for gun rights, which are protected by the U.S. Constitution's Second Amendment.
"I felt like it was our time to take a stand, because, you know, we're the ones in these schools, we're the ones who are having shooters come into our classrooms and our spaces", said Lane Murdock of Ridgefield High School in CT. "No guns under 21".
Broward school district officials said Stoneman High will be closed Thursday and Friday, and "all activities have been canceled for the rest of the week".