Zimbabwean police are investigating former ruler Robert Mugabe's wife Grace, accused of smuggling ivory worth millions to underground foreign markets, a state-owned weekly reported Sunday.The Sunday Mail said investigators from the parks and wildlife authority handed documents to police showing that the former first lady "spirited large consignments of ivory to China, the United Arab Emirates and the United States among other destinations".Police spokesperson Charity Charamba confirmed receiving a report but declined to elaborate when questioned by AFP.The Sunday Mail said the report accused Grace Mugabe of ordering officials to grant her permits to export the ivory as gifts to the leaders of various countries."Once outside Zimbabwe, the 'gifts' would be pooled together with other consignments of the product and routed to black markets," The Sunday Mail reported.A senior official in the presidency, Christopher Mutsvangwa, told the paper the government was tipped off by an unnamed whistleblower.KEEP UPDATED on the latest news from around the continent by subscribing to our FREE newsletter, Hello Africa.FOLLOW News24 Africa on Twitter and Facebook. "Police and whistleblowers laid a trap for suppliers believed to be working for Grace Mugabe," Mutsvangwa said."The culprits were caught and that is how investigations started. When we were confronted with so much evidence, there is no way we could ignore."The paper said police may question the former first lady soon.Grace Mugabe was tipped alongside the current President Emmerson Mnangagwa to succeed Mugabe, who ruled Zimbabwe since independence from British colonial rule in 1980 until he was forced to step down in November 2017 following a military takeover.She earned the sobriquet "Gucci Grace" for her lavish lifestyle.Zimbabwe has suffered rampant poaching of elephants, targeted for their ivory tusks which are used for ornaments and medicines.At least 400 elephants died from cyanide poisoning in Hwange, Zimbabwe's biggest national park in the northwest of the country, between 2013 and 2015.But parks director general Fulton Mangwanya said poaching had declined since Mugabe's ouster."Poaching levels have dropped sharply in Hwange because the market has been disturbed," The Sunday Mail quoted him as saying.