(Reuters) - Rick Probstein, one of the largest sellers of sports memorabilia on online auction site eBay, was at his computer working in his New Jersey office on Sunday when sale of items featuring former NBA superstar Kobe Bryant suddenly shot higher.

FILE PHOTO: Los Angeles Lakers Kobe Bryant slam dunks against the Sacramento Kings during their NBA basketball game in Los Angeles, California, January 28, 2011. REUTERS/Lucy Nicholson/File Photo

That was how the 50-year-old initially learned about the death of former Los Angeles Lakers star Bryant, who was killed along with his 13-year-old daughter and seven others in a helicopter crash near Los Angeles on Sunday.

“I saw an email ... Kobe sold, Kobe sold, Kobe sold ... I was like ‘Oh my God, what happened?’” he said in a telephone interview on Monday “It’s horrible. It’s a horrible way to get news when you are getting it through sales.”

Since the news of Bryant’s death broke, about 50 people have contacted Probstein to list related memorabilia items on consignment on eBay, he said. Probstein has also sold several Kobe Bryant basketball cards - some that were listed for more than $10,000 - along with signed basketballs, framed items and shoes.

As of Monday afternoon, more than 12,800 Bryant items had been sold on eBay Inc EBAY.O since news of his death broke, including a group of 31 trading cards with his picture that sold for $75,000, according to data on the site.

That demand has caused prices to skyrocket, according to Probstein, who said he has seen prices increase from five to 15 times more than the original sale price.

There were other measures of how Bryant’s superstar status - he was a league all-star for 18 of his 20 seasons - drove interest in his artifacts.

Mentions on social media sites including Twitter and Facebook about purchasing Kobe Bryant jerseys more than doubled on Sunday following the news of his death, according to social media monitoring company Brandwatch.

There were more than 69,000 social media mentions of Bryant’s National Basketball Association jersey on Sunday and Monday, the firm said, with many users sharing nostalgic stories about their first Kobe jerseys.

Bryant's book "The Mamba Mentality: How I Play" was the top-selling book on Amazon.com Inc AMZN.O as of midday on Monday.

On online luxury reseller The RealReal Inc REAL.O, searches for Kobe Bryant sneakers spiked about 30 times higher.