Searching a character in sql table and displaying all records in gridview that start with that character ASP.NET c#

Good day I am working on an ASP.NET C# application that searches a sql table and brings back the results in a gridview. I got it to work using the like operator but I realise that if I search a character it brings back any record with that character in it, what I want is if I search with a character I want all records starting with that character. It should also allow me to search normally, Here is what I did previously

//I have a connection manager class in my app code folder

 SqlConnection connection = connectionManager.GetConnection();

        SqlCommand myCommand = new SqlCommand();
        myCommand.Connection = connection;


        String str = "select PR_NAME_GN, PR_NAME_SURN, EVENT_PARISH, EVENT_YEAR, EVENT_TYPE, FS_IMAGE_ID from Jam01 where (PR_NAME_GN like '%' + @deceasedFirstName + '%' AND PR_NAME_SURN like '%' + @deceasedLastName + '%' AND EVENT_PARISH like '%' + @ParishOfDeath+ '%' AND EVENT_YEAR like '%' + @YearOfDeath+ '%' AND EVENT_TYPE like '%' + @TypeDeath+ '%' AND FS_IMAGE_ID like '%' + @ImgLocation+ '%')";

        SqlCommand command = new SqlCommand(str, connection);






        command.Parameters.Add("@deceasedFirstName", SqlDbType.NVarChar).Value = DeathFirstNametbox.Text;
        command.Parameters.Add("@deceasedLastName", SqlDbType.NVarChar).Value = DeathLastNametbox.Text;
        command.Parameters.Add("@ParishOfDeath", SqlDbType.NVarChar).Value = ParishoDeathtbox.Text;
        command.Parameters.Add("@YearOfDeath", SqlDbType.NVarChar).Value = YearofDeathtbox.Text;
        command.Parameters.Add("@TypeDeath", SqlDbType.NVarChar).Value = type_Death.Text;
        command.Parameters.Add("@ImgLocation", SqlDbType.NVarChar).Value = "";

        command.ExecuteNonQuery();

        SqlDataAdapter sda = new SqlDataAdapter();

        sda.SelectCommand = command;


        DataSet ds = new DataSet();

        sda.Fill(ds, "PR_NAME_GN");
        sda.Fill(ds, "PR_NAME_SURN");
        sda.Fill(ds, "EVENT_PARISH");
        sda.Fill(ds, "EVENT_YEAR");
        sda.Fill(ds, "EVENT_TYPE");
        sda.Fill(ds, "FS_IMAGE_ID");

        GridView1.DataSource = ds;

        GridView1.DataBind();


        connection.Close();

I need recommendation on how to rework the sql statement. I am kinda new to this so please bear with me.