If you are arrested, you should request to speak with the American Embassy in Harare immediately. The phone number is 263-04-250-593 from a Zimbabwean mobile phone, or +263-4-250-593 when dialing from the United States. This number is manned 24 hours/day, and the receptionist will put you or local authorities in contact with the Embassy staff. If you cannot reach the Embassy, try to contact someone locally who can.
For a comprehensive list of lawyers in Zimbabwe, please refer to the Law Society of Zimbabwe Lawyers directory on http://lawsociety.org.zw/directory