Police in Senegal have arrested the son of former President Abdoulaye Wade on suspicion of corruption.Karim Wade is suspected of illegally amassing about $1.4bn (£900m) during his father's rule, his lawyers said.Karim was a senior minister during his father's rule from 2000 to 2012, and was in charge of major infrastructure and energy projects.Investigators had set him a deadline of Monday to prove his innocence, after accusing him of corruption a month ago.His lawyers said they had submitted documents relating to his assets to a courthouse earlier in the day.'Minister of earth and sky' One of the lawyers, Demba Cire Bathily, told Reuters news agency that Mr Wade had been "forcibly" taken away."It was an arbitrary arrest," he was quoted as saying.Prosecutors announced an investigation into Mr Wade and five other former ministers last year.That followed the defeat of Abdoulaye Wade in the March 2012 presidential election by Macky Sall, who pledged to fight corruption.At the time, many Senegalese believed Karim Wade was being groomed as his father's successor.During Abdoulaye Wade's 12 year rule, Karim Wade held several ministerial posts simultaneously, including minister for infrastructure and air transportation.His large portfolio led to him being dubbed "the minister of the earth and the sky", but it also put him in charge of a large proportion of Senegal's government budget at a time of large-scale infrastructure spending.