How receive this Json?

I have this structure.. Cliente Side <-> Web Api Front <-> Web Api Back -> DataBase

So, When my Web Api Back send me the Json , i don´t know how to get the results...if someone help me. I am not showing the connection with database!

On the Web Api Front, the line var data = response.Content.ReadAsStringAsync().Result; gives me the Json Array with all the correct values. But i don´t know how send this to the ApiCall on the Client Side

[Service calling the Web Api Front]

public class ApiCall
    {
        static readonly string ApiUrl = "http://Localhost:1762/api/{0}/{1}?nomePesquisa={2}&nomeMae={3}&nomePai={4}&dtNasc={5}&nrg={6}&ncpf={7}";


        //buscar os dados com os parametros digitados
        public async Task<T> GetResponse<T>(string controller, string method, string nomepesquisa, 
            string nomemae, string nomepai, string dtnasc, string nrg, string ncpf) where T : class
        {
            var client = new System.Net.Http.HttpClient();

            //Definide o Header de resultado para JSON, para evitar que seja retornado um HTML ou XML
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

            var urllink = string.Format(ApiUrl, controller, method, nomepesquisa, nomemae, nomepai, dtnasc, nrg, ncpf);
            var response = await client.GetAsync(urllink);

            //Lê a string retornada
            var JsonResult = response.Content.ReadAsStringAsync().Result;

            if (typeof(T) == typeof(string))
                return null;

            //Converte o resultado Json para uma Classe utilizando as Libs do Newtonsoft.Json
            var rootobject = JsonConvert.DeserializeObject<T>(JsonResult);
            return rootobject;
        }
}

[Web Api Front calling Web Api Back]

[HttpGet]
        [Route("Envolvidos")]
        public IEnumerable<Envolvido> GetEnvolv(string nomePesquisa, string nomeMae, string nomePai, string dtNasc
           , string nRG, string nCPF)
        {

            DataSet lretorno = new DataSet();

            using (var client = new HttpClient())
            {
                client.BaseAddress = new Uri("http://Localhost:1762/");
                client.DefaultRequestHeaders.Accept.Clear();
                client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

                // Usage
                HttpResponseMessage response = client.GetAsync("api/nomes/Envolvidos?nomePesquisa="+nomePesquisa+"&nomeMae="+nomeMae+"&nomePai="+nomePai+"&dtNasc="+dtNasc+"&nrg="+nRG+"&ncpf="+nCPF+"").Result;

                if (response.IsSuccessStatusCode)
                {
                    var data = response.Content.ReadAsStringAsync().Result;
                    Envolvido envolvidoResult = JsonConvert.DeserializeObject<Envolvido>(data);

                }
                else
                {
                    Console.WriteLine("{0} ({1})", (int)response.StatusCode, response.ReasonPhrase);
                }


                return WHATTTTT?? ;

            }

        }

[WebApi Back]

[HttpGet]
        [Route("Envolvidos")]
        public IEnumerable<Envolvido> GetEnvolv(string nomePesquisa, string nomeMae, string nomePai, string dtnasc
            , string nRG, string nCPF)
        {

            DataSet lretorno = new DataSet();

            string connectionString = GetConnectionString();
            using (OracleConnection connection = new OracleConnection())
            {
                connection.ConnectionString = connectionString;

                OracleDataReader reader = null;
                OracleCommand cmd = new OracleCommand();
                cmd.Connection = connection;
                cmd = new OracleCommand("MOBILE.XAPIMANDADOMOBILE.BUSCAPOSSIVEISCANDIDATOSPF", connection);
                cmd.CommandType = CommandType.StoredProcedure;

                //variáveis entrada            
                cmd.Parameters.Add(new OracleParameter("ivnome",nomePesquisa));
                cmd.Parameters.Add(new OracleParameter("ivmae", nomeMae));
                cmd.Parameters.Add(new OracleParameter("ivpai", nomePai));
                cmd.Parameters.Add(new OracleParameter("ivdatanasc", dtnasc));
                cmd.Parameters.Add(new OracleParameter("ivrg", nRG));
                cmd.Parameters.Add(new OracleParameter("icpf", nCPF));
                //variáveis de saida          
                cmd.Parameters.Add(new OracleParameter("oretorno", OracleDbType.RefCursor)).Direction = ParameterDirection.Output;
                cmd.Parameters.Add(new OracleParameter("qretorno", OracleDbType.RefCursor)).Direction = ParameterDirection.Output;

                connection.Open();
                cmd.ExecuteNonQuery();

                reader = cmd.ExecuteReader(CommandBehavior.CloseConnection);

                //CRIO A LISTA
                lretorno.Load(reader, LoadOption.OverwriteChanges, "BUSCAPOSSIVEISCANDIDATOSPF");
                connection.Close();
                connection.Dispose();


                //CARREGO O DATASET E TRANSFORMO PARA IENUMERABLE E RETORNO SEUS VALORES PRO JSON
                return lretorno.Tables[0].AsEnumerable().Select(row => new Envolvido
                {
                    SUSPID = Convert.ToInt32(row["SUSPID"]),
                    IVNOME = Convert.ToString(row["SUSPNOME"]),
                    IVMAE = Convert.ToString(row["SUSPMAE"]),
                    IVPAI = Convert.ToString(row["SUSPPAI"]),
                    IVDATANASC = Convert.ToString(row["SUSPDATANASC"]).Replace(" 00:00:00", ""),
                    IVRG = Convert.ToString(row["RG"]),
                    ICPF = Convert.ToString(row["CPF"]),
                    MANDADO = Convert.ToInt16(row["TEMMANDADO"]),
                    OCORRENCIA = Convert.ToInt16(row["TEMOCORRENCIA"]),

                });


            }
        }