LOS ANGELES (CBSLA.com) — Technical problems that hit United Airlines, the New York Stock Exchange and Wall Street Journal website Wednesday were quickly deemed not malicious, but a former federal computer crime prosecutor said the system crashes may not be a coincidence.

Michael Zweiback, former chief of the U.S. Attorney’s Cyber and Intellectual Property Crimes Section in Los Angeles, cautioned that the outages took place within three “significant sectors,” which raises a red flag.

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“This affected crucial areas — travel and the most significant sector in the financial world,” Zweiback said. “We need to understand what took place in order to prevent the next one. We have to find out whether these were intentional attacks or malware that was probing the systems to determine whether there were any widespread vulnerabilities.

“This could’ve been a reconnaissance effort,” he said. “Although it’s plausible that these were glitches, it could also be more than coincidental.”

Each of the affected organizations said their networks crashed because of internal technical issues, and White House Press Secretary Josh Earnest told reporters there was “no indication that hackers were involved.

Clifford Neuman, director of the USC Center for Computer Systems Security, said he tends to agree, saying the malfunctions were likely not the result of a cyberattack, but caused by separate problems within three organizations’ networks.

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“These were individual system breakdowns,” Neuman said. “If you have multiple systems breaking down because of a common reason, then it really is significant. But in this case, what we’ve seen appears to be coincidental. These were probably independent failures that just happened on the same day.”

United grounded its fleet throughout the nation for a time Wednesday, and resulted in delays of about three dozen outbound flights at Los Angeles International Airport by midday. An unknown number of inbound flights also experienced some delays.

According to Mary Grady, also of LAWA, the airline notified LAX that its computer system was out nationwide, but by about 6:45 a.m., the computer glitch had been fixed.

While being questioned by Sen. Barbara Mikulski (D-Md.) at a hearing, FBI Director James Comey said he believed the Wall Street Journal outage was due to an unexpected flood of traffic in response to the New York Stock Exchange’s outage, according to TheHill.com.

Zweiback said it would probably take several days before details trickle out about exactly what caused the outages.

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