Can anyone point me towards any media coverage of the incident?
There is no media coverage, it's an open and shut case
Any confirmation that it was lithium batteries?
Remember that cheap nicads or nicads that have been improperly re-celled have caused fires through their ability to deliver enormous number of amps when shorted.
Due to the baggage restrictions on Lithium batts, nicads are making a comeback with media crews.
The luggage was described as a "black hard shell suitcase", this description does not exclude "pelican" brand style flight cases commonly used by film and TV crews.