Israeli authorities are investigating claims by US researchers that some investors may have known in advance of a Hamas plan to attack Israel on Oct. 7 and used that information to profit from Israeli securities, Reuters reports.

Research by law professors Robert Jackson Jr from New York University and Joshua Mitts of Columbia University found significant short-selling of shares leading up to the attacks, which triggered a conflict nearly two months old.

“Days before the attack, traders appeared to anticipate the events to come,” they wrote, citing short interest in the MSCI Israel Exchange Traded Fund (ETF) that “suddenly, and significantly, spiked” on Oct. 2 based on data from the Financial Industry Regulatory Authority (FINRA).

“And just before the attack, short selling of Israeli securities on the Tel Aviv Stock Exchange (TASE) increased dramatically,” they wrote in their 66-page report.

In response, the TASE referred Reuters to the Israel Securities Authority, which said: “The matter is known to the authority and is under investigation by all the relevant parties.”

A spokeswoman for the securities regulator did not elaborate, and Israeli police did not immediately comment.