Louisville-based Ventas Inc. filed a lawsuit claiming Health Care Property Investors Inc. sabotaged its efforts to acquire Sunrise Senior Living.

The lawsuit, filed in U.S. District Court in Louisville, says the Long Beach real estate investment trust “engaged in a calculated campaign to sabotage” Ventas’ $1.8 billion deal to buy Sunrise back in January. Ventas is seeking $100 million.

Soon after the deal was announced, Health Care Properties sued Ventas in an attempt to block it, claiming it not been given a fair chance to bid for the Canadian REIT.

However, a Canadian judge ruled in March that the deal would stand and that Health Care Properties and Sunrise were to stop all negotiations and allow the Ventas acquisition to move forward. An appeal by Sunrise was later denied.

Shares in Health Care Properties were down 16 cents to $34.71 in afternoon trading Friday on the New York Stock Exchange.