It turns out there was nothing substantial on the San Bernardino iPhone all along

The Justice Department and Apple spent much of the past few months in a bitter legal battle over whether Apple should help the FBI access data on a phone used by Syed Farook, one of the San Bernardino shooters.

Now that the FBI's cracked the phone - without Apple's help - one thing is becoming clear: there wasn't much useful information on it.

CBS News reports, citing a law enforcement source, says that "so far nothing of real significance has been found" on Farook's iPhone. The investigation is ongoing, according to the source.

This matches up with remarks made by the San Bernardino police chief in February, when he said that there is a "reasonably good chance there is nothing of any value on the phone."

In the FBI's defense, director James Comey and his subordinates have never claimed that there were case-breaking secrets on Farook's work-issued iPhone that he used to take photos during his day job conducting school cafeteria inspections.

Instead, Comey wrote that law enforcement owes the victims a "thorough and professional investigation under law" and that the FBI was just trying to collect all available information, and couldn't leave any stone unturned.

Throughout the case, the FBI maintained that its legal action was about one phone, whereas Apple argued that the government was trying to set a precedent.

On March 28, the FBI dropped its court order because it said it has managed to unlock Farook's iPhone without Apple's help.

The FBI has said that it hasn't decided whether it will share the details of the hack that it used to crack Farook's iPhone 5C. Apple attorneys have said that they won't sue to get that information, either, and that they are not even sure whether the FBI's crack works, considering they know nothing about it.

A lot of speculation has centered around how the FBI eventually cracked Farook's iPhone. Earlier this week, the Washington Post reported that the government paid a security researcher for a previously undiscovered exploit, or flaw that the FBI used to gain access to the encrypted data on the device. Security firms have paid at least $1 million for a confirmed "zero-day" iPhone exploit in the past.