Routes issue in Express 4

Noob - trying to set up CRUD using routes on Express4 and Node. I've got the following GET and POST routes working ok, but DELETE and PUT are giving 404, Not Found errors, which is strange.

I'm using Postman for Chrome and have set the Content Type to application/json, and this is working ok - i do notice that on the DELETE and PUT queries the header still notes that it's sending as text/html, rather than JSON, although I've set both the RAW settings to JSON, and the Headers content type manually to application/json.

var express = require('express');
var router = express.Router();

var mongoose = require('mongoose');
var Todo = require('../models/Todo.js');

/* GET /todos listing. THIS IS WORKING*/
router.get('/', function(req, res, next) {
  Todo.find(function (err, todos) {
    if (err) return next(err);
    res.json(todos);
  });
});

/* POST /todos listings THIS IS WORKING*/
  router.post('/', function(req, res, next){
Todo.create(req.body, function(err, post){
    if (err) return next(err);
    res.json(post);
    });
});

/* GET /todos/id THIS IS WORKING*/
router.get('/:id', function(req, res, next) {
  Todo.findById(req.params.id, function (err, post) {
    if (err) return next(err);
    res.json(post);
  });
});

/* DELETE /todos/:id  NOT WORKING*/
router.delete('/:id', function(req, res, next) {
    console.log(req);
  Todo.findByIdAndRemove(req.params.id, req.body, function (err, post) {
    if (err) return next(err);
    res.json(post);
  });
});

module.exports = router;

Also this is a routes.js script that is being imported into app.js (see below):

var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');


var routes = require('./routes/index');
var todos = require('./routes/todos');

// set our port
var port = process.env.PORT || 3000; 


//Requires the mongoose connection 
var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/todoApp', function(err) {
    if(err) {
        console.log('connection error', err);
    } else {
        console.log('connection successful');
    }
});

var app = express();
// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');

// uncomment after placing your favicon in /public
//app.use(favicon(__dirname + '/public/favicon.ico'));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, 'public')));

app.use('/', routes);
app.use('/todos', todos);


// catch 404 and forward to error handler
app.use(function(req, res, next) {
    var err = new Error('Not Found');
    err.status = 404;
    next(err);
});


// error handlers

// development error handler
// will print stacktrace
if (app.get('env') === 'development') {
    app.use(function(err, req, res, next) {
        res.status(err.status || 500);
        res.render('error', {
            message: err.message,
            error: err
        });
    });
}

// production error handler
// no stacktraces leaked to user
app.use(function(err, req, res, next) {
    res.status(err.status || 500);
    res.render('error', {
        message: err.message,
        error: {}
    });
});



// start app ===============================================
// startup our app at http://localhost:3080
app.listen(port);               

// shoutout to the user                     
console.log('Magic happens on port ' + port);

module.exports = app;