(CNN) Prosecutors will seek to put Nikolas Cruz to death for carrying out last month's massacre at a Parkland, Florida, high school, they announced in court filings Tuesday.

A Broward County grand jury last week indicted the 19-year-old gunman on 17 counts of premeditated murder in the first degree and 17 counts of attempted murder in the first degree.

In its filing, the prosecution said that, among the aggravating factors spurring its decision, were that Cruz knowingly created a risk of death for many people, his crime was aimed at hindering "any government function or the enforcement of laws" and that the shooting was "especially heinous, atrocious or cruel."

Another factor: "The capital felony was a homicide and was committed in a cold, calculated and premeditated manner without any pretense of moral or legal justification."

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